Happy Socks takes 25% off its men's, women's, and kids' socks and underwear via coupon code "HALLOWEEN25" during its Halloween Sale. Plus, the same coupon unlocks free shipping. Some exclusions apply, including outlet items. Deal ends October 29. A couple of best bets, with prices after coupon:

Happy Socks Unisex Halloween Cat Socks for $9 (pictured, $3 off)

Happy Socks Unisex Hotdog Socks for $9 (low by $3)