One thing I like to do is take advantage of a monthly used equipment sale by a major lfs around here. I get leakers and reseal them, but they haven't had anything over 75 gallons in a while.
When I bought my new 150 I paid $900. It came with an oak stand and canopy, glass tops, and a very nice 48' marineland LED system. I bought it new and they also delivered. It may sound steep but i thought that it was a great deal.
120 gallon 4x2x2 tank. Genx 1190 gph pump, nice lighting set up, ADHI 30g refugium, probably 100 pounds of black sand w/ mix of sea shell/coral, two 200gph power heads, 2 brand new heaters, all for 300.
Only thing about it I didn't like was the stand which I am going to build a nice 6ft long stand for putting smaller 24 inch long tanks at the ends to put my smaller community and feeder fish.
I currently am searching for a 6 foot long used tank with everything and I don't want to pay more than 400. The only problem is that I can only find 4' 120's in my price range
I just bought a 125 with stand, canopy,fluval405,air stones,heaters and a bunch of other small stuff for $300. The thing is to check the ads everyday because when a good deal comes along
the don't sit long. Good Luck
You can stay in your 1dollar per gallon rule if you are patient. Just last week I got a 150 with stand for 125.00. Check criagslist EVERY DAY and do a google search for a state specific aquarium forum. The mistake most people make is not being patient or not being able to walk away from a tank that is not in good shape.
I got a 90 gallon tank with glass tops, 48" jbj 4 bulb compact fluorescent light, and a new sealed in box fluval fx5 for $300. Not to mention the box of decor, was told it had no heater, then surprise, dug into that decor box and found a 300 watt glass heater. Sat on my 600 dollar budget for weeks waiting to find just that right deal.
Prices on tanks are really situational. There are some that may be in a hurry due to moving or some other reason. They end up selling a decent sized tank for dirt cheap. One prime example is my 180 Gallon. I bought it for $70 and it came with glass lids + metal stand. Tank needed some scrubbing but it was totally worth it. But the one thing you have to know is that it took me about 2 months of daily craigslist checking.