I have one that I want to sell, IMO, disc wheels are definitely out of the ordinary but they're not necessarily the best thing for commuting on (weight, tubular tires, fragility). Maybe fine for alleycats or just hanging out. I think they're best kept to the track (especially if they only have freewheel threads).

I would say you're not going to be able to find an affordable used carbon disc very easily, but you might have luck with a fiberglass one.