And double check your city regs. Some places don't allow ferrets. It would be a major bummer to spend the money to get all the supplies and a little guy only to have to rehome him. And no, just because a city bans them being kept does NOT ban the pet stores in the city from selling them.
A quick call to your local Animal Control would probably help, and if they are allowed they may be able to offer a hint as to local fosters/shelters/etc that have them.
P.S. Check Petfinder.com too!

P.S. Check Petfinder.com too!