That's unfortunately not true NCSGeek, it only applies to particular stores and/or certain items. Empire store items however are bound to the civ you purchase them on.
Have a look through the global market, there are quite a few store bought items for sale 3, 5 or 10 times the price the vendor asks for, some low effort traders like to exploit players lack of knowledge about certain items being available in a store. I've seen sparta blueprints, argos cows and various others items being pushed in the market.