Not that any high-schooler would believe it, but those old cell phones are worth something. Companies are selling reconditioned models in Latin America and the Caribbean, where wireless networks are flourishing and customers aren't as cutting-edge crazy as Americans. RMS Communications of Ocala, Fla., is buying and selling between 60,000 and 80,000 phones every month, says CEO James Mosieur. There's lots more out there. Every month more than 9 million phones are retired. RMS finds most of its phones through collections held by charity groups and companies. Now it's adding mall kiosks. Want to offer up your relic? Check out the RMS Web site, cellforcash.com. Or try other sites like cashmyphone.com and cellphonesforcash.com. Prices range between $3 and $90 for each usable phone.