I was given a 29 gallon tank for free from a co-worker who felt it was incompatible with his toddler. Of course since then I've dropped about $500 into the hobby (stand, appliances, fish, plants, books, et al).
Ok......I bought a 55 gal including stand, filters, pumps, gravel, lights, test kits, plants, heater, books, everything.....for $125.00.
I watched the want ads/merch for sale/ in my local paper. It's a nice tank and in excellent shape when I bought it and I am glad I have it.
Indeed, if you don't mind used tanks, keep a close eye on the classified section of your newspaper. You'd be amaze at how many ppl consider this hobby as a throw away hobby. After keeping fish for a little bit, and getting tired of all of them dying, many just give up and sell their stuff for cheap. You could also ask your friends to see if any of them have anything they could give/sell to you. I got myself a 70 gallon tank for free from a friend of mine... she even asked me if I wanted to take her 80 gallon tank off her hands... maybe when I get more room, who needs a sofa right?