See, you already have two buyers here on QL. ;)

There are shops that buy (and sell) used items (household and furniture, etc) at Haraj in Najma. But they will try to buy the items from you for the least possible price. Best thing is to advertise on QL because I guess you will get a better price. But if you are in a hurry and you want to sell your stuff in one go then your option is the Haraj.