E bay can be a really good bet especially if you are willing to put a little money into the project. Eg I got 2 4ft tanks on a double stand with lighting and filtration and then picked up new heaters from the guy cheap due to his being a cold water keeper. All for £115 and then as the filters were dubious to say the least I managed to pick up a pair of fluval 205 external canister filters for a bargain £20. The bargains are ther if you have time and patience. Also look at aquarist classified.