Huaraz in Peru is a hub for cheap trekking. There are 2 big mountains.
Cordillera Blanca - The most popular trek is the Santa Cruz trail.
Cordillera Huayhuash - Huayhuash circuit takes 7-10 days.
I highly recommend this book by Trailblazer.
https://www.amazon.com/Perus-Cordilleras-Blanca-Huayhuash-Trailblazer/dp/1905864639