Check out my temporary paint booth. I made the frame out of 2" PVC Schedule 40 pipe. I didn't glue any of the connections together, so I can knock it down and store it between paint jobs.
I am going to use the window in the garage as a place to put the exhaust fans. I'm going to try the eight furnace filters in the other end as an attempt to adequately filter incoming air.
I used 6 mil thick plastic sheeting as the covering. I am not finished, as you can see in the photos, I still have to install the zippers for the door. All the plastic is screwed to the ceiling using furring strips and the plastic sheeting will be rolled up against the ceiling when not in use. The sheeting is long enough that I can lay 2x4's on the floor to seal the sheeting to the floor. The sheeting will also be cut around the filters in order for the air to flow through the filters.
Total Cost: A little less than $200, but I already had the exhaust fans. I was lucky enough to find a supply house who had dropped the pipe when unloading and couldn't sell it for pressure use. I was able to buy what I needed for a very low price. I will also add more lighting.
http://community.webshots.com/album/61919910OiWAHW