Keep on eye on PetCo, they just had a sale this last June/July for $1 per Gallon for tanks up to 55G. So you could get a 40 gallon for $40 which is a really good deal. That's if you have the room for it of course, heh. I'm pretty sure that sale happens twice a year, so around December/Janurary expect to see it again. I've seen background for sale for as low as $1 a foot I THINK, maybe it was $2 a foot. This was at a fish store in Ypsilanti, if you're anywhere near there.