I'd
highly recommend getting it done professionally. If you do it wrong, then you could crack your paint. The process involves bolting the fender roller to the hub, heating up the fender lip with a heat gun, and
slowly rolling the metal under itself while it's still hot and flexible. All hell can break loose if you've got any bog in the fenders, so it pays to take a magnet and move it around the fenders to make sure there are no 'weak' spots.
Phone around your local tire shops to get prices as they can vary from place to place. It was nice and cheap to get mine done on my 7th Gen Corolla and only took about 45-minutes. Very worth it, especially if you don't want to be constantly spending money on new tires