oh my god people, you are just recommending random unicycles to him.
what kind of riding are you looking into doing (trials, freestyle, mountain, commuter, touring)
a great overall beginner unicycle is the torker lx, which comes in 20" and 24". the downsides to this unicycle are that it has a uncomfortable seat, and a single walled rim. the upside is that it is cheap (around $100 new). These unicycles are not good for trials or mountain stuff though, because of the skinny tire and weak components.
If your looking to go longer distances the torker ax 29" is pretty good, featuring an aluminum alloy round crown frame, and it is still easy enough to learn on. However, it still has an uncomfortable seat and slick pedals, along with ridicoulously long cranks.
For someone your size the torker dx 24" would work well for both trials and mountain stuff. It is around $250 new, but it has a slightly better seat, bombproof rim, and splined cranks with grippy (if cheap) pedals.
I only listed torker unicyles because they tend to run much less expensive than other ones, even though there are lots of other brands (KHU, Koxx-One, Qu_Ax, Nimbus, Bedford ect.)
I hope this helps a bit…
-Miles
oh yeah, places where you can buy them new are Unicycle.com, Bedfordunicycles.ca, compulsioncycles.com, and renegadejuggling.com.
These are all in North America…
edit:
that unicycle is way better than the DX in my opinion, get that if you get a trials.