Nobody likes paying for delivery. In fact, unexpected shipping fees are one of biggest reasons people abandon online shopping carts right before buying. Store owners know this human quirk well, so they use a clever psychological tool called a free shipping bar to turn a potential roadblock into a sales tool.

A free shipping bar is a colorful banner placed at top or bottom of a website. It clearly states a goal, such as "Free shipping on orders over fifty dollars." As you add items to your shopping cart, bar updates in real time, saying something like, "You are only fifteen dollars away from free shipping!"

This live update taps into our natural desire to get a deal. Shoppers would often rather spend an extra fifteen dollars on a physical product they can keep, like a pair of socks, than spend five dollars on shipping fees that disappear into thin air. It turns delivery costs into an interactive game, encouraging buyers to explore store and add more items to their carts.