Squealing under the hood of my 93 chevy silverado v6... A/C ?

I have changed the idler pulley and the smog pump. It seems to have enough tension on the belt so i counted out the tensioner. I took belt back off turned all pulleys by hand and it seems the ac pulley makes the most noise. my ac hasnt worked for awhile and i havnt needed it. do u think its the ac pulley? if so how much am i looking at? and can i just byp that pulley? or do you think it might be something els?