Yes you give back a core, but the maker only looks at the cost of the raw material.... you give back your core and get the same core $ you always did, and it goes to a recycler, then it gets recycled and goes back to the battery maker as raw material. However, the price of recycled material fluctuates according to he market price for the metal (new or recycled go up and down together) so your core trade doesn't affect the makers cost unless the battery maker and recycler are one and the same.