Our blog post covers this in detail. We recommend using Kayak.com or Google Flights to see what is out there in terms of flights.
You may also want to take a look at the prices at flyforgood.com or call 1-877-359-4466 to speak to a person. They get humanitarian rates from airlines, and GEEO is registered with Fly for Good as a nonprofit. If you purchase a humanitarian rate flight, you will need a supporting document from GEEO. Please request this from us after you purchase the tickets. Note that humanitarian rates are not available for all flights to GEEO destinations and are sometimes higher than tickets found on Kayak, Travelocity, Orbitz, Expedia, etc. Often the layovers are long and sometimes impossible to navigate. Look very carefully at the offer before purchasing your ticket.