My New Shop!! Yiippeee!

Looking for some type of exhaust fan for my shop. I would like something that is mounted in the ceiling and has shutters so the heat or air will stay in the shop. Can someone tell me why these fans are so dang high!!! They want $500 for these fans!!

http://www.ebay.com/itm/36-Inch-Bel...529?pt=LH_DefaultDomain_0&hash=item1e61cb6cf1

It's just a stupid fan for crying out loud!! lol