The bag unit is a Delta (just for correctness, not a recommendation) that has worked well since I added an American Fabric Filter .3 micron bag to it BUT, all of this eludes your original request for inexpensive and simple. 3M, in their wisdom, after purchasing AO Safety, stopped making my favorite face mask:
Street price about $13, long lasting filters, low interference with direct and peripheral vision. It was perfect; so of course it must be discontinued and replaced by those big ole honkin' twin cartridge vision impairing half masks. Ron Keeble went above and beyond the call of duty in analyzing the fit and visibility restrictions of the
Lee Valley model for me, which I now have. It is a close second to the no-longer-available AO Safety unit in comfort and visibility interference but, that varies with your head size and shape.
*** Hmmmm, I just noticed that I am not to blame for my long-winded-ness, I get it from my dad ***
Anyway, cheap and quick protection is a mask (shop long and hard, if you don't like it, you won't wear it). If you want the layer of dust that coats the clothes dryer under control, a shop made unit as Carol suggests is worthwhile; commercial units available
. I use mine to scrub the air (while I leave the shop) if an activity has created a mess (like free hand routing of MDF).