Amazon has an fulfilled face mask product available with quick one-day Prime shipping on sale for $9.99 (affiliate links below):
You can get similar products on eBay with price fluctuations between $5 and $10 (currently $8.18 is the lowest I see, at time of this writing). This Amazon deal is useful if you need some masks quickly or you don’t shop on eBay.
Also available on Amazon with very slow shipping from out of the country (not FBA shipping) for $3.19:
