Noise coming from belt area
 

I am getting a weird loud grinding noise from the belt area of my 2000 Mazda Protege ES 1.8l. Its not the noise that I got when my belt and water pump was having issues. This is different. What does that sound like? My buddy seems to think its an idler pulley. How hard is that to change? How expensive is that if I were to pay someone else? Thanks for the help.