I'm buying them in bulk online. Depending on your location, there will be wholesalers, and Amazon is probably dependable, although I've never used the latter.

https://www.amazon.com/3M-Particulate-Respirator-8210-Pack/dp/B008MCUZZS/

You don't have to worry about counterfeit when it's from the 3M store.

Bulk buying online is the way to go, not just for masks but for everything. Every trip to a shop avoided is a mask saved. Well not exactly because you can reuse the masks a few times as long as the elastic is still good and you leave each mask 3 days between uses.

I buy them in bulk from home despot in amerikkka

I live in Taiwan and manufacturers here have n95 equivalents (taiwanese gov standards) that are very cheap.

Masks were invented in Taiwan btw

Ya I never see N95s in stores nowadays.

I got some of those reusable silicone masks with the disposable filter inserts (there's a few brands that are basically all the same). I don't know how effective they are exactly but the filters are cheap.

Amazon, currently. I pay about $20 a month for masks, and I often see deals on 3m n95s.

There are some medical supply places online where you can sometimes find deals on bulk masks. Haven't used any of those sites personally, by a friend of mine got about 400 3m n95 masks for about $150 a year ago.

Generally n95s are good for at least 8hrs of straight use from what I've seen. So if you are only grocery shopping or going on public transit or other relatively short time periods, you can re-use the same high quality one for a while.