Olx.in is a very good cocetual site to trade stuffs. You can sell anything there and can even purchase anything from there. There is no third party required to make the trade happens. The seller can directly contact the buyer and they both negotiates the price accordingly. olx.in even started chat option, so you don’t have to provide them with your numbers or address until he/she was ready to accept the basic deal that you have described in the description box.
I also got a roommate through this site. So, I, personally, love this site as I got so many things with substantially lesser than expectation.