I'd start with checking craigslist and classifieds in your area If you're looking to save some money.
There should be plenty of em wheels on craiglook - just punch in "pottery wheel" and your city and go:
Hi everyone. I just found this forum and was hoping to get some advice. I have taken basic wheel throwing classes for about 1 1/2 years. I think I'm ready to purchase my own wheel for my home. Can anyone offer any suggestions for where I might find an affordable wheel? I have been looking on craigslist, but no success so far. Also, where do you store your wheel? I live in North Carolina, and I wanted to make sure that the humidity wouldn't harm the components of the wheel.