we had a big tank sale at both petco and petsmart late summer early fall. not sure about the 1$ per gallon.. but up to 55 sounds right. You're better off talking to your local LFS and letting them know your looking for a deal. Mine gets deals threw his distributor about every few monthes. quoted me 400$ for a 125,stand,tops, 2 overflows. ect. the wholesaler gives him a deal 1-2 times a year on the set-up. =D waiting for the next one. where from anyother store includeing the big chains a 125 w/out overflows will cost me just teh tank itself about 300$ cheapest. Also talking to your LFS about a discount on buying multiple tanks may work out for you.
and it never hurts to let them know your looking for tanks. LFS and employees of chains know their regulars fairly well. and going threw them to get a used tank ime is fairly common. I've gotten some great deals over the years from people just wanting to unload a tank. and not knowing about craigslist/ect.
"putting the word out" should work either way. either looking for a new or used tank.