Well simplicity is greatness. Dont bother with a lot of tutorials telling u to yank motors, solder this etc... Mountains out of molehills!
Go to Walmart, buy a 5 inch battery powered fan for $5. I bought these little quarter size mirrors in the Crafts dept. Get a Green Laser on ebay.
Take the guard off the fan and throw it away. Glue the mirrors directly onto the blades of the fan. Done.
I took a 2x4 about a foot long. Mounted the fan base to the 2x4 on one end. I just taped the button on the laser so it would stay on. Mount the laser at an angle to hit the mirrors. Its just trial and error to get the right angle. I just used a small wood block and zip tied it down in the right position.
Add fog.... DONE. A lot of tutorials will have u yanking little motors, doing this and that. Why? Its all done for you! Just use the fan!!!