I got a 180 gallon, with a metal frame stand for it, a installed filter for it, hood(s) and the bulbs all for $360. The tank I bought was built just for me, it's brand new and it was delivered to my apartment.
I was looking into buying a 24x36x72 or something similar for my upgrade tank. The price for that tank with all the features above I think would go for $500? The prices don't drastically raise from size to size, they just start out at a certain price. As always, bigger the tank, the cheaper it will be when buying per gallon, as far as I know.