I put a 20" hardware store fan on the wall, and hinged it so I could swing it in front of the window when I wanted it on, but swing it out of the way when I wanted the blinks closed. It works well, but I may add another one to move more air.
I use two box fans in the garage during heating season. One on the floor and the other is about 12' off the floor on a shelf. I made the shelf out of 2x4s and a piece of OSB. The fan is bolted to the shelf so it doesn't fan off. It's purpose is to push warm ceiling air across the ceiling and down.
I put in an 18" 2speed fan with louvers in my garage, actually the fan just shipped yesterday so it will be installed once it arrives. Pumps out 3200 CFM
I bought 5 ceiling fans at Lowes on closeout for $17 each. I work with a couple of guys that run fans & dehumidifiers in their garages & they say that it keeps it pretty nice.