I've been a T-Mobile subscriber for several years now. This weekend, I upgraded our phones, and wanted to re-use the several ringtones and wallpaper I had downloaded during those years. The guy at the store said, "Just call Customer Service, I'm sure they can give you a credit or something". Unfortunately, I got the "or something" part, which was an apology. Turns out, you have to re-download the ringtones and they won't issue any credit. What a ripoff. I can't use something I already paid for!
If you own a cell, DO NOT buy ringtones! The companies are already making a killing for their services, and ringtones are their cash cow.
Instead, check with your phone manufacturer to see if they sell software to let you create your own ringtones and wallpaper. Since I got the V360, they have a package that does just that. This software also works for RAZRs and other models, too! Check it out at: http://www.bvrp.com/customers/motorola/upgrade/US/