$6 lost sock

I own one pair of $12 socks. They're Woolsmart socks and are the most comfortable feetgloves known to mankind. I only wear them when I have to go shopping with my mother or know that I will be stuck in the Chicago airport overnight. I just did my laundry. There's one sock missing. It's worth $6. How in the world? Why? What do I do now? Where is my sock?