People keep saying you can buy masks online, so I went onto Amazon.com.mx to check. There are NO N95 masks for sale. If you read the reviews for the small variety of masks, you soon discover that they are all crap. Usually too small, or the elastic breaks, or you don't get what you ordered. Any masks that looked like they might be worthwhile had no reviews, and there is no point risking ordering those. Mercadolibre does have them, and some of the reviews are good, but as with Amazon, many have no reviews, and that is dangerous.
There are a couple of guys with a table beside Tony's who are selling masks, gloves, and antibac gel and soap. Their thin masks (at 5p) are pretty poor, although they are enough. Their N95s (the type with a metal band, but no valve) are $125p each, which is ludicrous. I own one that I got for spraying trees at a farmacia for 15p before this all started. their gel is also way overpriced at $125p. Supply and demand.