So $1 masks are only "Duckbill" masks, which look kind of stupid. But they're clearly low cost and have very high surface area / breathability. Also, real N95, so major benefit for sure.
https://accumed.com/30-pack-fda-cleared-niosh-n95-surgical-r...
These straps kinda suck though. I recommend carrying a few extras somewhere since the straps may snap throughout the day. I'm still looking for a better mask. For all of its faults, this one is available today and at the promised $1 price too.
The BNX duckbill masks used to be $1 per. But they seem sold out. Keep an eye on them just in case they come back into stock. https://bnx.com/products/bnx-50-pack-n95-mask-respirator-nio...
The Kimtech 53358 Duckbill WAS $1 each just a month ago. But their prices suddenly skyrocketed to $1.50ish from most sources. EDIT: If you buy 300 of them, you should get close to the $1/each price, but I want to "test" them before dropping $300 buckaroos on it...
EDIT: WB Mason is selling the Kimtech Duckbills at $50 per 50-pack, so that's $1 each: https://www.wbmason.com/ProductDetail.aspx?ItemDesc=Kimtech-...
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I'm not sure how much I trust Amazon's supply chain for proper N95 / NIOSH approved products. A lot of Amazon's stuff are 3rd party shippers and/or 3rd party suppliers instead of official sources, and comingling is an issue.
If its $1.50 from a proper medical store, then the $0.80 price at Amazon is probably too good to be true. If we're paying extra for the N95 rating, I'm willing to pay extra for proper supply chain.