How can i change my cell phone number without having to pay a fee?

i want to change my cell phone number because i keep getting annoying calls and i'm sick of them. however i have T-Mobile and they charge $15 to change the number. how can i change it without having to pay that fee?How can i change my cell phone number without having to pay a fee?
You can't, you either have to ignore the calls or just pay the fee.