Cheap hotels in Marrakech are everywhere, but you won't be able to find them before you arrive online or with a travel agent. Wait until you arrive and then make your way to the main public square in the middle of town. Once you arrive, head down some of the smaller alleyways that lead off of the main square, and you will see various signs pointing to small riad style hotels. Many of these hotels are just as clean and nice as some of the more expensive counterparts, but may be lacking in amenities which makes them much cheaper. You can always negotiate from the price that they quote you.