ya you don't often see 40 breeders for cheap. i actually have a problem with hording tank way to many in storage just ameks sure you don't horde to much.
I really like 40g-breeder tanks for the depth they provide, plus they seem more stable to me, being half as wide as they are long. And 50 is a very good price, less than half what I've seen at Petco, for example. If you're sure it's in good shape, I'd go for it.
Aw man, I heard back from the seller, and he had already sold it. However, he said it wasn't a 40g breeder and that that's why he sold it off. Next time..