Amazon offers its Prime members the Original Penguin Men's Waffle Crew-Neck Shirt in Mazarine Blue for $13.67 with free shipping. (Non-members can spend $35 to qualify for free shipping; otherwise, it adds $5.48.) That's the lowest total price we could find by $9. It's available in sizes from S XL to XXL.

Note that it's available in four other colors, starting from $15.19.