With RATs in short supply, there is one big thing you can do to remain safe in shared spaces, particularly indoors - mask up in an N95/P2 respirator. Here's a thread-o of some common brands at the best prices I can find them in stock. I have no affiliation with any of them! A couple of points to start:
1. Yes you can reuse! Let your respirator dry out between uses
2. For proper use, mould the nose wire over your nose properly
3. I'm going to include some of the most popular masks but i'll point out that they're at inflated prices 😠😠😠