PicSay Pro ($3.99). This app lets you do things like add word balloons and stickers to any photos you’ve got stashed in your Gallery app. (PicSay Pro creates duplicate copies so your originals stay intact.) The word balloons let you turn fun pictures into hysterical cartoons; the stickers let you add hats, hairstyles, beards, and so on to your pals and frenemies’ mugs. Use various tap, pinch, and spread gestures to get everything looking just how you like. And for less frivolous editing, there’s a fully stocked Effects menu that lets you adjust photos along every dimension you’d expect: exposure, saturation, tint, and red-eye fixes (to name just a few). A couple dozen filters, frames, and distortion effects (neon, rainbow) add up to a seriously fun way to get more for $4 than a mere cup of coffee. Photo fans will end up spending loads of time playing with this thing.