How much would it cost to get my cell phone number changed?

I have AT%26amp;T

If it costs anything, is there anyway i can get it changed for free?How much would it cost to get my cell phone number changed?
you would probably have to cancel your plan and get a new sim card.How much would it cost to get my cell phone number changed?
If you tell them that your number got onto some list and you are receiving a bunch of unsolicited calls, they may change it for free.