HSN offers the NFL 3-in-1 T-Shirt Combo in
16 11 team designs (Colts pictured) for $17.98 plus $1.99 for shipping. That's $27 off list price and the lowest total price we could find. It's available in sizes S to XXL, although not in all team/color combinations.
Note, new customers can apply coupon code "142694" to cut it further to $15.28.