GAP Adventures is an adventure tour company based in Toronto Canada. They specialize in small group trips to Latin America. Their trips are very low priced, with a local payment required in the arriving city.
They keep their prices low by using locally owned 2 star hotels, by not including most meals or tours, and by having a tour leader rather than a tour guide. On the trip, all accommodations and internal transportation (bus, train, boat, plane, horse, etc) is included in their price. There is a lot of free time when tours can be purchased, locally, for the sights one is interested in. Or the free time can be used to explore on one's own.
Their type of trips work out very well for the semi independent traveler who does not want to worry about hotels or transportation arrangements, does not want all meals included, and does not want to pay for tours they may not be interested in.
The tour leader is required to speak the local language fluently. They help with any problems, provide departure and local information, and arrange things like the bus/train/plane tickets. They get the group checked into the hotels and will arrange group dinners if the group wants to eat together.
As for the tours that are included, my experience is that the local guides that GAP uses have been excellent. And the included tours are for the experiences that is the usual purpose for the trip, such as a guided tour when at Machu Picchu.
Their clients range in age from 20's to 70's. If you want to travel in a way that exposes you more to the local culture, don't need 5 star hotels. and can be flexible when traveling in out of the way places, GAP Adventure tours might be right for you.