What can I do with my back seats?

I have a 2017 mustang fastback and was thinking of removing the back seats. There isn't enough room for any adult to sit back there and I am planning on replacing them with a custom speaker box with subwoofers, amps, etc. Before I begin that though, I need to figure out what to do with the actual seats. Is there anyplace that will buy car seats? Would I be able to sell them on craigslist? It seems like a waste to throw perfectly good seats in the dumpster. via /r/cars http://ift.tt/2tCd1ap