There are very limited accommodation options at Machu Picchu itself--most who don't head back to Cusco look in the town of Aguas Calientes for hotels close to Machu Picchu. This town offers an array of different lodging options, ranging from extremely cheap and basic to considerable luxury.
The cheapest hotels in Aguas Calientes are to be found along the railroad tracks. These don't consist of much more than a place to lay your head. If you're prepared to spend a bit more, there are a number of places along the river, some with balcony views of the river. A number of the better hotels have adjoining restaurants. There are also a couple of decent lodges, one extremely close to the ruins, but be prepared to pay a premium.