Zazzle Instant is an iOS app that lets you add your own pictures to a ton of different products, including Macbook and iPad sleeves, iPhone cases, messenger bags, playing cards, and a whole lot more.

Vivian Dye is a smart woman. And so it took less than six months of selling customized golf merchandise on Zazzle, the most prominent online marketplace with three Zs in its name, for her to figure ...