Costco is good for EVERYTHING (a store where you can buy meat, cheese, tennis balls, and CASKETS is a winner in my book). BUT a store like Fresh Market/Whole Foods has a good selection, too. Trader Joe's if you have one (we don't) is a "treasure hunt" store where they rotate products and based on its novelty, makes one inclined to buy (Costco has similar items, but no where on the scale of Trader Joe's). You'd be amazed at some of the stuff you end up with leaving there.
-nmr