I got a got a 30:1 gear reducer on ebay for $50. That turns a 1725 RPM
motor into 200 fpm when you have 14" wheels. This assumes direct drive
- no belts between motor and gearbox input. Belts on the fast side of
the gearbox would be OK it you want to play with the speeds. Or as
Gunner said, a VFD and 3-phase motor would be even better. Ebay is
lousy for pricing on a lot of stuff but things like gear boxes and
3-phase motors go cheap. VFDs require more watching to get cheap on
Ebay so Dealers Electric is probably a better bet for that.