As one of its daily deals, That Daily Deal offers this Men's U.S. Sarcasm Foundation T-Shirt for $5.99 plus $2.99 for shipping. That's the lowest total price we could find for any such t-shirt by $6. It's available in sizes S to XL. Deal ends October 21.
Note it's available in XXL for $6.98 and XXXL for $7.98.