Greetings badspawn, T-Mobile does NOT charge any kind of fee for upgrading your phone or for upgrading your service plan...the only differance is that on a plan upgrade/downgrade you only pay the pro-rated differance unless the plan doesnt take effect until the billing cycle date. If your inquiring about a phone upgrade i recommend calling your local T-Mobile corporate owned store and ask the representative about the process and what it entitles.

Enjoy!

I don't know if this counts as upgrading, but my friend in Boston lost his cell phone, didn't have insurance for it, so T-Mobile gave him another but made him sign on for another year, otherwise he would have had to pay full price ($200 or so) for the new phone.