- At Amazon.com, buy one pair of ExOfficio Men's or Women's Underwear and get 50% off a second pair. (Discount applies in-cart.) Plus, Prime members bag free shipping on all orders. (Non-members can spend $35 or more to qualify for free shipping; otherwise, shipping starts around $5.) Before discount, men's boxer briefs start around $16 and women's full cut briefs start around $12.