In March 2008 I went with Power Trips Inc to the Dominican Republic for a 2 week humanitarian trip.
Power Trips Inc.
My trip was focused mostly on rebuilding schools so kids could have an actual classroom to learn in. Also we raised money and collected medical and school supplies for the schools.
I know a group of people who went in March 2007 got to work with a school for the deaf. Every trip is different so it's hard to say whether or not you'll get to work with people with disabilities.
I know that Judy runs trips during reading week for university students and also a trip in August as well.
Fees, I think it was around $5000 or something can't really remember anymore. But because Power Trips isn't like a huge organization they depend on the fees to help pay for supplies that will be needed for the trip. Some people depend on donations to help fund their trip.
I can tell you that this trip was unbelievable. Sometimes people don't believe me when I say this but this trip was life changing for me. It really opened up my eyes and it was during this trip that I realized what I wanted to do with my life. Words just cannot describe how amazing this trip was. It's not Africa, but some of the living conditions of these people is just as devastating.
You could contact Judy, the founder of the organization, for more details about the trip. As far as I know, she goes on every single trip and is there with you the whole time.
Good Luck in finding a trip that you like. It's an incredible thing you're doing and the memories you make and experiences you learn on these trips are things you can't obtain anywhere else i think.
Oh, also you might want to try Free the Children, they do trips to Kenya, China and India in the summer. I haven't heard much feedback about those trips but I plan on going next summer to see for myself.