I hate buying 4 and throwing away 3 since the only one that wears out is the driver’s.
Most manufacturers and distributors sell their car mats in sets of 2, 4, or the entire car. I know that you can get just one mat at a time from ExactMats. They will custom fit your BMW but they won’t be logo mats :
If you don’t want Exactmats (I bought them to protect my good carpet mats) then here’s a link to an info site that covers most of the North American manufacturers of car floor mats:
What I did, as I alluded to above was buy a good set of carpeted mats and then I protected the drivers side mat with an Exactmat vinyl mat. That way my carpeted mat always looks good and doesn’t get worn out by my heel moving around.
They might sell seperately here for your model http://m.eagleday.com/e395seinpr.html, this is where I bought for my M5 in a set of 2