pulley

My AC unit is screaming, garage quoted me over a grand to replace it. I called a dealer and they said there are aftermarket by-pass pulleys available but they wouldn't tell me where :p Any help would be appreciated :)

How is it going everyone I'm in the process of replacing my serpentine belt and I need to replace the automatic tensioner pulley as well. I'm wondering if anyone can give me some technical advise on how to remove it. your help would be grate fully be appreciated as it is my only car for work.