There is so much mis-information and ignorance about this virus. Starting with the use of anti-bacterial things, - does not help, as this is a Virus!!!
It is not actually airborne, which is why people are so much at less risk of cross-infection when outdoor - yet, people seem scared to open their windows - when airing their rooms out would be better, than covering everything indoors with bleach, etc.
So, with masks. The normal non-medical standard masks are easily available - they can be purchased on-line and in most pharmacies and supermarkets. These are thought mainly to protect the wearer from passing on anything if they cough and sneeze. There may be a small residual amount of protection for the wearer if they actually come into contact with someone with this virus and get coughed or sneezed at by the person.
In enclosed places, such as underground trains, and buses it can do no harm to wear these, (it is now actually compulsory). In large stores, where there is reasonable social distancing the chances of someone with this virus actually being close enough, for long enough to someone else in that store to pass anything on is minimal, whereas in small shops wearing a mask may be of some help.
No idea why people where them when they are outside, or sitting in their own cars. Perhaps people see them as some sort of magic talisman.