ELI

Charges program fee plus daily fee; visit lengths seem to be from two weeks to six months (maybe more?). Nonprofit.

http://www.greenforceusa.org/

CIEE: year-long teaching opportunities abroad. Small program fees ($1000-2000ish?); some airfare covered?, monthly stipend, some programs with free lodging.

Volunteer International

Searchable list of lots of different volunteer organizations.

Peru program: http://www.globalcrossroad.com/peru/volunteer_in_peru.php
Cost: $1090 for 2-week volunteer only, $1490 for mini-venture
More details soon

Peru programs: Macaws of Peru, Archaeology of Peru’s Wari Empire, Amazon Riverboat Exploration
Cost: $2949-$4549
Length: 12-16 days
Not adding more details because it’s out of our price range. But oh so cool.

Peru program: http://www.globeaware.org/Content/trips/peru/peruprogram.php
Cost: $1090
Dates: 8/4 - 8/11, 8/18 - 8/25, 9/1 - 9/8, 10/6 - 10/13 (more earlier/later as well)
Programs:

Andean Village

“Volunteers may help teach children in the village school, help build simple Lorena stoves (which greatly reduces fuel consumption and increases health of the home’s inhabitants by reducing smoke), with community projects and repair, and […]