Sam's Club offers members the Izod Boys' Polo and Short Set in several colors (Navy pictured) for $12.81 plus $1.50 for shipping. (Non-members must pay a $1.28 surcharge.) That's the lowest price we could find by $10, outside of the deal below. They're available in sizes XS to XL.

Note: Amazon offers it starting from $14.94 with free shipping for Prime members.