Just make sure they only charge you the $15 fee when you call the number. I just got back the other day and flew US Airways. When I called the number on the DME paper left on our door, they tried to charge $20 per bag. I had to explain to the person on the phone that US Airways policy is $15 per bag when prepaying. You pay $20 only if you do not prepay for your baggage and check them at the airport.