Single-use masks are usually pale blue or white medical style masks, also known as surgical masks.
Don't use masks with holes or a valve, as you will breathe out the virus if you have COVID-19. The main value of wearing a mask is to protect other people.
Buy single-use masks from reputable retail outlets including chemists and supermarkets.
Dispose of single-use masks in a general rubbish bin, not in the recycling.