I got mine from a scrap yard for about $40 each. SS is going for $1.25 a pound around here. I have also heard of asking a liquor store for any nonreturnable kegs they may have. Good luck!
I got mine just that way... non-returnables at a liquor store. Apparently there's a time limit on a deposit. Strange policy if you ask me... but as I made out on the deal I'm not complaining!