I saw double-sided mats at Sam’s Club last week – grey on one side, primary colors on the other. I don’t remember the price,.but it seemed to be a good price.
We have had 8 of the primary color mats since my dd was just starting to crawl on our wood floors. She too hit her head a couple of times, but more often than not she landed on her nicely padded rear end. I never let her wear socks unless they had lots of grippers on the bottom. Now I’m doing the same things with my ds.
Another advantage of the mats is that they help make it more comfortable for you (or another adult) to sit on the floor. You can grab one or two of them and have a nice little portable cushion for anywhere your child wants to sit and play with you. Plus, I use a couple of them in front of the tub so that my knees don’t hurt so much on the ceramic tile floor.