We have used Ecophones, a similar outfit, for the last year (
www.ecophones.com). The advantage of this site is that they pay for everything, working or not. BUT, they pay about $1.00 for most, standard, basic phones (like the one I use!). For Example, the LG Chocolate phone will get you $5.00 if working and in good condition, 50 cents if broken. They don't accept chargers or cords.
We've gotten about $100 over the past year.
Most places take other electronics as well and some items such as video games and inkjet cartridges.
I can see this as a good fundraiser if you have large volumes - they all provide free shipping so there is no cost to the team. If you start a campaign at your school, put out collection barrels, you should be able to make several hundred dollars this way. but you do need high volume. This could also be used as a community service project, to providing recycling services.
I'm sure I don't need to point this out, but if your team is interested, make sure you should do a comparison of the prices offered by all of these sites. My guess is that they don't differ much in the long run.