I am basing this pattern loosely off of one I found online because when I attempted to make those, they turned out nothing like the picture, even though I followed the pattern. They became more like garter-stitched ankle warmers. I just did this in a bright purple yarn I found at Wal-Mart, and they fit me perfectly!
Red Heart Super Saver Worsted Weight Yarn in Amethyst
Size US 10.5 (6.5 mm) straight knitting needles
Darning or tapestry needle
Legwarmers (make 2):
Cast on 30 sts.
Row 1: * k2, p2 * to last 2 sts, k2
Row 2: * p2, k2 * to last 2 sts, p2
Repeat rows 1 and 2 until the work measures 15 inches, ending on row 2.
Now, knit as follows:
Row 1: * k1, k1p1 into next st, p2 * to last 2 sts, k1, k1p1 into final st
Row 2: * p3, k2* to last 3 sts, p3
Row 3: * k3, p2* to last 3 sts, k3
Repeat rows 2 and 3 for 6 more rows.
Bind off in rib.
Sew edges together.
Here they are!