there is two different pulleys
the idler is to the left of the alternator pulley and below.
It is very easy to change.
The tensioner pulley is attached to the spring loaded tensioner. You have to decompress the tensioner, and remove the tensioner (along with the drivebelt), then you can remove the pulley which is attached to the back of the tensioner.
That too is very easy to change.
I think the idler pulley, and the tensioner pulley are the same size pulley, and I think mine cost like ten bucks.