Hi
I was wondering: How much do unicycles depreciate over time?
The minute a person drives a new car off the lot it loses approximately 10 percent of its value. By the end of the first year, that car will lose an additional 10 percent on average. And up to 50% of the value lost over the first five years.
How was it different for unicycles? Why?
Would a 2013 model in good condition ever sell for 50% less in 2018?
Is there a “bluebook“ for unicycle values? 
That’s hard to say but I’d guess it’s much easier to tell if a unicycle is in good shape than a car, the latter being a more complex machine which may look great on the outside but could harbour all kinds of nasty secrets under the bodywork. By contrast, if a unicycle looks battered it almost certainly is.
Assuming your unicycle looks to be in decent shape, has been used for non-aggressive ridding (road, for instance), and is not a very old model, I reckon you could get a decent amount.
If your uni is made by a well-known brand (e.g. Kris Holm) that probably adds to the appeal, similar to the higher resale value of a MacBook versus an HP laptop.
Finally, a higher price may be easier to justify if the buyer is able to inspect and test-ride the uni personally before buying, especially in the unicycle is genuinely in good shape. You could refer buyers to your unicyclist.com forum profile so that they see you are a reputable person.
Supply and demand: if you really want a good unicycle, you grit your teeth and pay the price. Most people don’t want a unicycle at all, and most of the people who do expect to get one for a trivial amount. Someone who wants one for a novelty or gimmick or fun present won’t pay the extra for a KH with all the trimmings.
However, if you can find a buyer who’s really looking for a good uni, and you have a good uni, you’re in a negotiation. If it’s clean and almost as new maybe you’d get 50% – 75% of new price for it. If it’s well used with normal cosmetic damage, and is only a standard model that they could easily find elsewhere, maybe considerably less.
It depends how fast they want to sell it. Because unicycles don’t change hands as much as cars (there are a lot less of them, and us), a seller might not know when the next offer will be made and may accept a lowball one. I should have held onto my 2nd generation Coker that I sold at U-Games (2010) for $200. Original offer was for $250 but then the buyer cried poverty. I should have offered him a tissue.
(Note: the above proves that I have actually gotten rid of at least one unicycle)
Of course not, nor is there the equivalent of a CarFax (USA only, I think) or even books/websites that list all the variations of unicycles on the market over the years. So most buyers and sellers are taking their best guess.
Some think the uni is worth way more than everyone else does. You can see a lot of those on eBay, where somebody wants $200 for a rusty old Schwinn from the 80s or something. Others, again, are more interested in making it go away, so they offer better pricing.
Around here (the forums, Facebook unicycle areas, etc.) there’s much more experience and knowledge of what’s out there, so people sometimes ask if a seller’s price is fair. Sometimes it’s yes, very much, or sometimes we recommend the buyer tell the seller that they’re nuts. 
We can’t even call in an expert appraiser, like they do on Pawn Stars (American TV show about a pawn shop with high-end stuff). Or we can, but only virtually, and use photos to make an estimate.
Hey William!
You’re trying to add a uni to your stable? Or you’re trying to sell one of your 36"?
Hope you’re good!
True! There is an interesting thread in the “for sale” section of the forum where the unis for sale on other sites are listed. Quite a lot of those actually…
the only uni I sold again was my schlumpf 29", which I had bought for 2100 Eur or a bit more. don’t remember and after over a year I sold it for 1700. Had only ridden 1 ride of 5km with it , but I couldn’t get the hang of shifting gear or mounting in high gear. I have enough other uni’s and decided I don’t need it. The 36" goes fast enough for me and behaves the way I expect.
Last year I also bought a 20" freewheel and after a hard backwards fall decided it wasn’t worth investing time in. There are enough things I can still learn with a normal uni. At some point will sell that one too. Even fewer peeps ride a freewheel uni than a normal uni.
I think this disproves the adage, “There is no stupid question.”
Cheap unis are virtually worthless, second hand. My first uni cost $10 at a garage sale but admittedly it needed pedals. Beginners can take their pick of something to try learning on for $30.
A better quality ones aren’t that much more expensive. A few of my unis cost between $50 AND $75 though I have upgraded parts of them later. The Qu-Ax Profi was only $50 and I paid $75 for an Impact Athmos. Both very nice wheels with ISIS hubs, double wall eyeletted rims and stainless spokes.
Whole unis are often cheaper than parts. I bought the Athmos to get the wheel for my old KH which had an Onza hub.
$200 to $350 can buy a quality uni but they are usually snapped up pretty quickly. I saw a Nimbus 29 in as new condition at $150 languish for over a month. A bargain for the Dominator 2 wheel and Freeride saddle but I mostly wanted a disc frame so it didn’t tick the boxes for me.
At the top end of the spectrum I paid $1K for my Triton (Titanium frame 36) which, including accessories such as KH 29 inch wheel, a variety of tyres, two sets of Spirit cranks with discs and Shimano Saint pedals, carbon fibre seat, handlebar, would probably be twice that to replace new.
Top end parts in good condition such as a Titanium frame or Spirit cranks are always worth something.