Amazon takes up to 81% off a selection of superhero t-shirts for boys. Better yet, Prime members qualify for free shipping. (Non-members can spend $25 or more to qualify for free shipping; otherwise, shipping costs $4.98.) Plus, sign up for Amazon's Clothing Store email list and get a coupon good for an extra 20% off. (You will be e-mailed the code.) That puts most at lowest-we-could-find prices by significant margins.

A best bet is the Marvel Boys' Spider man Headless T-Shirt (pictured) for $12.99 before the coupon, $10.39 after. With free shipping, that's the lowest total price we could find in any color by $11. It comes in sizes 4 to 7.

Amazon Prime membership is $79 per year; however, Prime is free for college students for one year, and free for parents and caregivers for three months.