I'm not sure this actually helps you, but I'm pretty sure there's a statutory Buyer's Remorse period where you can cancel within 14 days with no penalty.
It's not -- I just signed up for a postpaid plan on T-Mobile yesterday, and the receipts included the first and second months' bills (for service and taxes).
If you do it on the web they make it very plain that $0 is due now. They do say the plan will be $45/month but there is absolutely no indication what their additional fees will be nor what the taxes will.
I'm in California. Maybe you are in a state where they actually have to provide this information?
I'm in Oklahoma, which traditionally doesn't have much in the way of consumer protection or information laws. It's possible, though I think it's probably because I bought it in a physical store.
