Hanes via eBay offers its Hanes Men's FreshIQ Boxer Brief 5-Pack in assorted colors for $13.13 with free shipping. Excluding the mention below, that's the lowest price we could find by $2, although we saw it for a buck less a week ago. They're available in sizes S to XL.

A close price: Walmart has them for $13.96 with free in-store pickup.