Going back years we’ve kept a stock of N-99 masks due to the smoke generated by the wildfires here. I’ve also had a few of the reusable (washable) masks that work quite well for smoke.

I have a few 27”x27” cotton bandanas. Bandanas have been mentioned in this forum on many occasions. They are useful if you have filter material to sandwich between the two layers when folded, but there’s still an issue of the mask fitting correctly. Smoke particles are one thing, COVID-19 aerosols are another matter entirely. The N95 Face Mask Activated Carbon Filter might work. (You need to cover your eyes too.)

Sorry for your situation in light of the COVID-19, but masks have been sold out of the brick&mortar stores for weeks and as stated Amazon is also pretty much out. Buying basic first aid and survival items is best done while the supplies are available, not after the crisis is well underway.