Book the Inca Trail in advance with Travel Tour Group tour operator. There are two types of travel agency that will try and sell you an Inca trail tours: registered tour operators and middle men, otherwise known as endosars. The registered tour operators are a small quantity that run, sell, and operate their own Inca Trail Treks.
All operators will need you for a 50% deposit which is generally NON-REFUNDABLE. It is non-refundable simply because the MINISTERIO DE CULTURA does not give back the tour operator any money when a passenger cancels, changes a date or name wrong. The tour operator then has to re-apply for a new permit if passengers change dates. The Inca Trail tour operator have different Payment methods.
There is no such thing as a WAITLIST / CANCELLATION LIST. If any agency / operator tells you that they can do this, they are simply not telling the truth and are operating illegally! Its as simple as if a passenger cancels their space is not given to anybody else - period!