The best advice I've gotten for this (from a veteran hopper, she does 16 in one weekend) is to go with a list of things you're looking for. For example she was looking for a solid yellow that matched a homespun focus fabric. Another friend that went with her was looking for fabric with ladybugs on it. They helped eachother out, didn't spend nearly as much as they could have, and it became a kind of treasure hunt.