An interchangeable foundation bag, foundation bag system a method of using the foundation bag system is described. In one embodiment, an interchangeable carrying bag system, is provided which includes a discrete inner foundation bag having an inner surface and an outer surface; at least one outer bag having a top periphery, an inner surface, and an outer surface; a first zipper portion connected to the foundation bag; and a second zipper portion connected to the top periphery of a slipcover. The foundation bag, foundation bag system, and method in various embodiments, may preferably use a reversible/non-reversible liner and a reversible/non-reversible handle.