Cusco sells the Inca Trail, and everything that exists because people cannot get on it. The Trail itself is capped at 500 permits a day including porters and guides, sells out months ahead, and may only be run by operators on the SERNANP licence list — every trekking company below is on it. If the permits are gone, the alternatives are Salkantay, Lares, Choquequirao and Ausangate, and they are not consolation prizes.
Prices cluster tightly and the real differences are group size, equipment and how the porters are treated. Two of the companies here are known specifically for the last of those.
The rafting and multi-sport operators are the other half of the town, and worth knowing if you would rather be on the Apurímac than in a queue at Warmiwañusca.