For big stuff, and dry goods, if you want the best prices, then driving to Lancaster to That Fish Place/That Pet Place is worth it once in a while. Their prices will be lower than smaller places. Petco doesn't ever have much in terms of marine equipment; Wild Side will order equipment but I usually just buy via mail order. I have had mixed luck with fish from all of these (TFP>Petco>Wild Side in my experience), but corals I've gotten at TFP have been fine. Other people I know would never buy another fish from TFP. I suspect that all of them are hit and miss with that regard. Petco and Wild Side won't give you any fish warranty, though. I've done mail order fish more often than anything else, probably.