Tulum Pueblo is the actual town: a grid of small streets either side of the main highway, with the bus station, banks, supermarkets, mechanics, dentists, and almost everywhere a Tulum resident lives. It is loud, busy, and a little chaotic — small motorcycles weave between the colectivos and the tourist taxis — but it is also where you can eat well for a fifth of beach-road prices.
Avenida Tulum, the main spine, is lined with restaurants, dive shops, and travel agencies; turn off it onto the side streets and you find taquerías, fruit stands, juice bars, and the city's small market. Stay in the pueblo if you want the cheaper Tulum and don't mind the bus or taxi out to the beach. Eat in the pueblo even if you stay on the beach.