Amazon offers Prime members the Hanes Men's Classic V-Neck T-Shirt 6-Pack
in White for $12.88
with free shipping
. (Non-members can spend $49 to bag free shipping; otherwise, shipping adds $5.48.) That's tied with our mention from a week ago, $2.15 per T-shirt, and the lowest total price we could find by $3. It's available in sizes S to XL, although not in all sizes.
Note that some sizes will take one to two months to ship.