I made masks out of an old sheet. Friends who don't want to sew have done the no-sew options. There are tons of how-to videos on the net for all types.
My mother got one from a neighbor who was making bunches of them to distribute. They were the standard pattern with elastic around the ears. The elastic doesn't fit well and the mask is too small to cover enough area so the whole thing is mostly worthless. I found that using shoe laces for ties that fit around your ears is better. You can adjust to your individual face to make a better fitting mask. That way, you aren't always fiddling with it to keep it where it's supposed to be. I started with one that ties behind my head, but that is harder to tie with my hair getting in the way, and the ties around my ears are easier.
If you have a sewing machine, or access to one, they are very easy to make. Find some cotton material that is closely woven enough so you can't see light through it, but you can breathe through it. They don't have to look pretty, nobody is going to get up close and personal to make sure the seams were ironed and are straight.
