My son is 14, and an avid skateboarder. He wants to start on a unicycle and I am looking to get him something to start with. I have read about sizes and styles and it looks like a 20" trial style may be appropriate. I am also however not adverse to getting a basic starter for him. Can some one recommend a solid website or community to find a cycle for him (new or used)? Some of the prices I’ve seen are fairly high. Thanks very much. 
In the US, craigslist is a good place to look since many people buy them, give up, and eventually need to dispose of them when cleaning up the garage (showing up at a unicycle event and asking around is another). A serviceable starter unicycle should be available for less than $100. Compare the “club” line at unicycle.com to get an idea of what you would pay for a starter one new.
Anyone can ride a 20 if the seat height is appropriate - that may mean sawing down the end of the post, or in some cases buying a longer one. As long as it’s a standard size (7/8 or ~22.2mm, 1 inch or 25.4, or the 27.2 of some heavy duty unicycles) that’s not a big deal - a new post ranges from $10-20 unfortunately plus maybe $10-12 in shipping. For someone tall a 24 inch wheel can offer some advantages - it responds a little more slowly and is more fun to ride distances on, while the future of the 20 is more towards developing small area tricks and skills - so in the end it depends on interests. Unless the frame of a 20 itself is too large to fit your son even with no seat post showing at all, a 16" wheel should be avoided.
A “trials” unicycle is somewhat of a specialty device, and may not be as suitable for learning as a more plain 20" - also typically a lot more expensive due to the more solid construction, though occasionally someone sells one cheaply.
One thing to keep in mind is you can buy once or buy once a year or earlier.
Not sure where you live but unicycle.com USA/UK/EU or bedfordunicycles.ca (call Darren for best service) in Canada is good too.
Dumping money into your wheel is the most important part of this. If he is coming from a sk8ing he will likely want to emulate similar riding as he does on a board. A cheap unicycle will not last long. just my $0.02.
-Philip
The thing about an expensive unicycle for a beginner who has never tried one is that you don’t know if they will actually persist in interest enough to figure it out.
A $50 used unicycle can likely be resold for $50, either if they give up or if they take to it like a fish to water and want to trade up.
A $300 unicycle may be a lot harder (or at least slower) to sell without taking a > $50 loss.
An option for a parent could be to get the $50 used learning unicycle, and present it with an explicit bargain - when you can ride this 100 feet or free mount and hop 10 times or whatever, we’ll get you a better one.
If you decide to get a 20 inch off Craigslist and the seat post is too short, Home Depot has longer ones for $12 and free shipping (home and/or store depending) if there’s one nearby you. I’ve bought a few and for learner unicycles they work great.
http://www.homedepot.com/p/Fun-Fun-300-x-25-4-mm-Unicycles-Seat-Post-659308/205151492
Advice thus far seems good.
Exactly.
Basically you have the choice between:
a) getting a starter unicycle which will be cheap on which he can learn but then soon you will need to upgrade to a high quality trials unicycle (maybe in a few months if he’s persistent).
b) or buying a high quality trails now (used is also fine). A good trials unicycle is about $300-500, used varies but usually >$100.
Both will be fine for learning and as has been said, anyone over about 4’ can ride a 20", you just may have to adapt the seatpost by cutting it down or buying a longer one.
If you think he’s going to stick with it, then get a trials unicycle because it is virtually unbreakable. With a background in skateboarding I will assume that if he learns to ride he will soon be hopping and jumping and thus thrash a basic steet unicycle (as an analogy think about doing BMX jumping with a Walmart bike).
As has been said, if he ends up not sticking with it, then your loss will be less on the cheaper one.
Or if you can find a good deal on a used trials unicycle that would be the best. I actually learned on a 24" muni and as far as I know there’s basically no disadvantage to learning on a trials (it’s just more expensive as it’s strong and durable).
I learned on a cheapy basic uni, and actually despite persisting and now owning a trials uni it was a sound financial decision. Because I now own a very nice trials uni with mostly very high end parts, which I’d never have considered buying before learning - if I had bought a proper trials uni before learning then I’d have got a basic mid/low end one, which I’d then have wanted to upgrade to something a lot nicer (in the same way I have with the mid range muni I bought a couple of months after learning - I don’t regret that purchase either, but it would have made better financial sense to buy a high end one at that point).
Some of us buy a unicycle about once a year anyway. 
And it’s a pretty cheap sport despite that. I still occasionally ride my <$100 beginner’s unicycle FWIW.
Wow, unicycles from Home Depot. Who’d have guessed?
“What kind of unicycle is that?”
The other advantage to buying a cheap uni first is that you won’t know what you want until you have some experience.
Was actually just out practicing neglected skills on my “cheap” craigslist learner unicycle that I started on two years ago.
Unfortunately I paid more than it was really worth (it had been advertised as a better model than it was), but was excited to get one and get learning, so declined the seller’s offer to take it back. Now that I regularly ride much larger and better unicycles, while I could sell it, it still has uses, and if I wanted to get it out of my apartment, I’d be more likely to take it to relative’s and leave it there for use on future visits, or loan it to a friend or whatever… I’d guess a lot of us have a spare basic unicycle stashed in a closet or garage rafters.
This is very true. I bought a “good” unicycle brand new when I could just barely ride my learning one, and I made the most ambitious purchase that seemed sensible at the time. But within a couple of weeks, I was realizing that if I’d waited just one week more, I’d probably have chosen something that better fit my developing personal interests (I bought a 26, but ended up wishing I got a 29). It wasn’t until a few weeks ago (almost two years into the hobby) that I decided upgrading again was justified.
Get a 20" Torker
I spent $50 on a cheapass 24" that got me nowhere. Seat post would always slip, cranks loosen, cheap tire/tube always losing pressure, and seat vinyl started ripping.
Learning process is very abusive to the unicycle, so it’s gotta be ultra tough.
Got nowhere(probably too big, also). Finally shelled out $150 for a 20" torker. That worked and a great tough little uni. Thick seat post with “double” M4 clamp ring, that didn’t twist every time you fell. It’s mid priced between cheap foreign “toy” and “pro type” nimbus or KH’s. I ride a 24" nimbus now which cost about 2x the Torker, but I appreciate the better quality, mechanics(splined cranks, Aluminum parts), big tires($50+) and performance. As a beginner I would never spend $300+ for a unicycle.
Also, get the kids some soccer shin guards, too. Unicycle riding is way tougher than skateboarding, because you can’t just ride passively. Just riding a unicycle is a “trick”.
By the way, “dad” should give it a try before passing it off to the kid. Good luck.
I learnt on a uni I bought for $10. It had a terrible saddle, a too short seat post and a skinny tyre. It made learning a lot more difficult then it needed to be.
The three riders I have since successfully passed the skill to all preferred my trials uni. The fat tyre and relatively long cranks make it more controllable. All three were riding in control in under an hour in the saddle.
I still have every one of my unis including the original one which I use for beginners, especially young children. I have upgraded it with a saddle and a tyre from a wreck that was given to me. I still ride all of them.
Thanks!!!
I appreciate everyone’s help. I will take a look at the Club 20" on unicycles.com and the Torker Unistar LX 20" and likely get one of those to see how he does. Also, I appreciate the suggestion, but Dad will not be trying it before son. 
I would think a trials type tire, being much wider, less PSI and having more knobs, is harder to learn on than a standard 20". Basic turning, for example, is harder on that type of tire/rim than say a “club” 20".
While these are decent examples of a basic design, buying either of them new is probably not a great investment. They’ll lose close to half their value the minute you unpack them (a more expensive unicycle would drop by about the same absolute amount, but proportionally quite less)
Rather, the idea with a temporary solution like that is to buy it used and then either resell it, or retain it as a minimum cost backup.
Save the new purchase for the “goal” unicycle, rather than the “enabling” one.
WTF??? Please elaborate! What could they do in under one hour of saddle time???
I think the OP should be warned that it takes most mortals longer to learn than what you described above. My neighbor, a 13 year old boy, was riding after less than one hour in the saddle, but I wouldn’t use the word control to describe his riding.
I do agree, though, that a trials setup is great for beginners. I believe that, had I started with a trials uni, I would have progressed faster.
Hey wait a minute! The “impending disaster that never quite happens” is the the Eureka moment of unicycling.
Everything that follows is just refinement.
You sir, have been quoted. And I did not upgrade my quote lightly, as it was a cool quote, spoken to me in person by Bodfish. In your quote you have summed up much of the unicycling learning process.
G’day Rich, I wish your son all the very best with this new adventure.
I don’t think you will be disappointed if you get either of those unicycles you are thinking of.
I have 3 sons (currently 12, 10 and 8 years old) and they all can ride fairly well. My eldest learned on a Unicycle,com club 16" unicycle (he was much younger than your son at the time). The other two learned on 20" trials unicycles. You can see them ride on my son’s You tube channel - OLOW Unicycle
My eldest convinced me to try out unicycling just before my 40th birthday. He really wanted to ride with me (makes me feel a bit special), and so I thought I should at least give it a go. I purchased a $10 used 20" unicycle (well really used much - the guy had a go and just didn’t stick with it) and learned on that. It was a really crappy unicycle, but did the job. I have found another thing I love doing with my boys.
I suppose I am telling you this in the hope that maybe you might think about maybe possibly one day having a go. =) Initially I found learning pure frustration, particularly as I had seen how quickly my boys were able to get going, but once I started making progress it became (and still is) a great challenge.
I posted about the three training sessions with my elder son on this thread. His natural ability is extraordinary. I put it down to BMX. He looked like a rider right from the start. He has his own uni now, a Koxx K1 we got on Gumtree.
My other son was riding fairly reliably in straight lines on smooth surfaces after an hour.
The third successful learner was just a week ago. He was already an accomplished skater and well experienced at doing extended wheelies on motorcycles so he had the sense of balance. His other big asset was dogged determination to do it. (I bet his legs were jelly that night.;))
After a few runs across the soft grass it was clear he was getting the idea. Then out onto the concrete footpath. After an hour he was able to negotiate a slight curve on the path. However he was still a bit hit and miss, mainly depending on how well he started.
Another guy at the same session was showing potential too. Unfortunately I didn’t have a post and saddle with me to properly match his leg length so he was on the little kid size learner with too low a saddle. Otherwise I think he might have been riding by the end of the afternoon.
I’m rearranging my gear and anther saddle is in the mail. Next time I take unis to a party I will be sure to have something to suit everyone.
These riders were all guys between 25 and 35. I think they make the best learners, especially when in each other’s company.