$5 - 55 gallon
Out of the blue my parents called on their cell that they had seen a fish tank at a yard sale. From the dimensions they gave me it sounded like a 20 or maybe a 30 gallon. They asked me if I was interested, and I said yes if was cheap... I have a 20 and a 45 running now, and another 20 in the garage and a 10 for a QT. They said when they got back from the errand they were running and if the tank was still there they would call me.
A couple of hours later my father called and said, "its bigger than I thought" He gave me the dimensions over the phone, I plugged it into a calculator online and told him that it was a 55 gallon tank. Then he told me that the people holding the yard sale were packing it in and they told him to make an offer. Not knowing what the tank could be worth he said 5 dollars... And I guess they did not want to have to haul it back into the garage.
I drove across town and paid my dad for the tank and now am the proud owner of a 55 gallon long tank that is missing its center brace. once I clean the tank really well I am going to get a piece of glass cut to silicone in for a center brace.
So far all I have is the tank. I will have to build a stand and most likely a cover. The only bad thing is the best spots for tanks in the house are on either side of the fireplace. And my wife's tank is in the wider alcove. I will have to move hers over to the other side of the fireplace and set mine up.