30 pairs of women's white no-show socks $13.48 shipped

Graveyard Mall has got a 30-count pack of  Womens no-show white socks for $12.99.  Use promo code CLOTHING50 at checkout to slice that price in half to $6.49.   Shipping (unavoidable) is $6.99, so your total will be $13.48 shipped, which works out to $0.45 per pair of socks.

There doesn't seem to be a quantity limit, so if you'd like to order two packages (60 pairs of socks), your shipping will be $7.99, which averages out to $0.35 per pair of socks.