LightInTheBox offers the Arsuxeo Men's Cycling Underwear Shorts in Black for $7.98. Coupon code "SO1318511" cuts that to $6.98. With free shipping, that's the lowest total price we could find by $3. It's available in sizes S to 3XL.
Note: Uncheck "Add Shipping Insurance to your order" during checkout to remove the 49-cent fee.