What's in a mask? Well it is basically an air filter; the more filter layers, cleaner the air but it is also about the fit and seal.
The WHO has made specific recommendations about when to wear a mask and most importantly to recognise that you must also perform hand hygiene and risk minimisation - a mask alone will not protect you.
There's an abundance of mask types out there, from home made to cheap imports as well as the brands you know.
Three M happens to provide some great resources in this area and I'll link them below.
Essentially, the more layers in your mask the greater filter efficiency, perhaps some sort of mask is better than no mask but you need to be sure you are getting what you are paying for.
This table below talks about particle filtration masks used in healthcare, I have not included simple surgical masks (3ply) in this posting.
You will see that "P2" is the Australian Standard but in specifications is quite similar to other commonly found masks N95, FFP2, KN95. Depend on where you live or work, you will have access to different types of mask.
Equally important is the fit. Here's a guide that covers most styles of mask.