Dollar tree used to sell everything for $1: I don't know if they still do or not. The products they sell are limited, and very, very, very cheap. It is amazing, really.
Dollar General and Family Dollar both sell things over a dollar.
Coincidentally, I just heard on news radio this morning that Dollar Tree was one of the few, if not the only, still sticking to the max $1 per product model.
Dollar General and Family Dollar both sell things over a dollar.