If you need a simple face cover for use in public transport or because you are looking after someone who is medically vulnerable to COVID-19, and aren’t able to make your own fabric mask, you could get one of these washable face masks with replaceable filter from Vistaprint.
They are not manufactured to any medical standard. The designs are a bit dull; this white one with the drawn hearts on it may be the nicest, but there is also for example a light blue one with smilies and a dark blue one with dinosaurs. They cost £17 and a pack of 10 filters cost £6 and delivery is free (checked on 8 May 2020). No, I don’t get a commission. https://www.vistaprint.co.uk/masks/