A few years back, most of the school age girls I saw...

[3catwoman3]

...at the pediatric office were wearing mismatched socks. One of the moms told me that there was a store called Mixie's that sold socks in sets of 3 - a mix of patterns in the same color combos, like plaid, polka dots, and flowers all in pink and orange, or blue and green, etc. No longer in business.