Those are MadyLegs, made with love by her Mommy.
Target has three packs of women's fashion knee socks for six bucks. Cut the foot off, fold the raw end down with a strip of No Sew in between the layers, iron on low heat on both sides (no steam), and bam! you have (insert.your.child's.name.here)Legs.
And you also have three pairs of ankle socks that match your kid's leg warmers. What more could you ask for six whole dollars? That's like, a dollar each.
This Mommy loves things for a dollar.