Donnai, keep in eye on Craigslist in your area - I've seen some great deals, though there is someone in Lawernceville that offers a lot at a rather high price . . . right now there seems to be a group of rather high priced ones, but it goes in cycles.
A Singer is a good one to start with as parts are almost always available, and there are a lot of them out there with worn decals and such so they aren't something a collector is going to want and that keeps the price down.
Like Steve said, there are tons (literally, as these are heavy machines!) of them out there. If you just want to jump in, find a nice 66 side clamp or a newer 15 in a treadle for $50 and go from there.
this one would be a good starter treadle, I'd offer $50 unless it comes with a good set of accessories. Cabinet is in rough shape and machine is nothing special. (Personally, I'd save up about $200 and then watch for something much nicer to come up)
http://atlanta.craigslist.org/nat/atq/4181691940.html
Ohh- if this one had been available while I was down there . . . but that is because this decal pattern is rare and the cabinet is in nice shape - and I don't own either yet! This one would need a lot of TLC becuase it is a rare decal pattern and you would not want to damage it. Seller does not know what they have, and thinks the high price is because of the stuff that comes with it - that is really only worth about $50 total. I'd try to get it down to $200 - and let them keep the puzzle box if needed!
http://atlanta.craigslist.org/nat/atq/4178501618.html