The lowest cost and simplest solution is to use a box fan (or two, if you really want to move a lot of air) with a MERV 13 or above filter attached on the input side. A 20 inch box fan moves about 500 CFM of air, so a one car garage (about 12 x 20 x 10) would have 100% of the air moved through in about 5 minutes. Whether that will be functional depends on which way your garage faces and where your normal wind is blowing - but if you can put one fan pointing out at the end away from where the air will be coming in, it should work fine.
This combined with a Shop Vac and small cyclone collector (like a Dust Right) to capture larger chips and sawdust gives you the best you can do without installing a larger and more centralized dust system (which is pricey).
I have a one car garage/shop and want to keep the airborne dust down as much as possible. I could install a filtration system. However, I was thinking of simply installing a vent fan and bringing in fresh air from one end of blowing it out the other end of the garage.
If I need to heat the garage in winter, this won't work. However, it seems to be a better option than hoping to catch the dust in a filter.
Anyone have experience with a simple fresh air system to keep the air clean?