Masks..

[babychange12]

Where is the best place to get masks?
What are the best masks?

Assuming you are asking in good faith, you are better off not spending your money on something you are unfamiliar with. Even if you were familiar it needs to be used properly.
Otherwise, places like Screwfix might intermittently still have them but I imagine they are focussing on selling to large organisations now and won't have the stock.

Masks are for preventing spread from the wearer not for self protection. They also deteriorate quickly and become less effective.