Tampu Restaurant Bar
Open to hotel guests only, also high prices.
Officially, you are not allowed to bring any food or water bottles into the park, and must check these in at the luggage storage at the entrance. In practice, however, bags are rarely searched, and most people have no problem getting a small bottle of water and some snacks in with them, which you'll definitely want, especially if you're planning to stray from the central set of ruins. Buy these beforehand, as they're much more expensive at the site itself. Don't even think of leaving a shred of trash behind you.
The concession stand near the entrance of the site is appropriately overpriced given their captive audience. Once in the site, there are no food or drinks for sale, though it is possible to leave and return.
Tinkuy Buffet Restaurant
A casual lunch buffet. The food is decent and the restaurant quite busy at peak times. A discounted train + buffet ticket is available on certain trains from Peru Rail.