Where can I get a decent sized tank for two fair goldfish cheap?

I have two goldfish from the fair. I know the rule 10 gallons per goldfish, but I can't afford a new 20 gallon tank. If I had money to, sure, however that is not the case. They live in a large bowl, I feed them everyday, and please don't say they are going to die. I got them on Monday and they are still healthy, happy little fish. I know because someone helped me install a 10 gallon tank the other day. They looked at the fish and said they were very healthy looking. As for people who tell me go get a 150 gallon tank for the two of them, why don't they start a goldfish rights club. They can have a mascot goldfish named Flippy who lives in a 300 gallon tank all by himself with 2 filters and all that. I'm sorry that I am not rich, so I was wondering however, if anyone new a place besides craigslist (looked there) that I can get a cheap aquarium. If not, I am afraid the bowl will have to do.