Ive had tons of free tanks, i get given one every other week. but what ive payed for is.... Juwel rio 400 with external/heater etc 100 quid. or my 6x2x2 with stand/filters/lighting/heatlamps for 65 quids so not much when converted to dollars!
I helped my friend build a plywood 90 gal and after a couple months he decided to move to another city. He didnt want to take it with him so its all mine, for free. $70 worth of mbuna, light, filter ect.
I just got a 90 gallon oceanic with stand and canopy, basic T8 light, sump(with protein skimmer), heater, a few bags of live sand and a small bag of salt worthy for 5 gallons(lol, why bother putting that in a 90 gallon set? plus it was already hard as a brick)
Years ago I went out with a girl and her father had a 55g tank that he sold me for 50 bucks, then I broke up with her. That was when I was in high school, over 18 years ago. Im old.
Now more recent, 3 years ago I picked up my 90g with stand and light along with a rena 3 stage filter all for 100 bucks. Craigslist is great.
Best deal for me was a AGA 125g tank, matching Oceanic stand, XP3 filter and a 72" Coralife CF lighting system with 6 moon lights all for $250. Deal was so good I gave the seller an extra $50.