Photoshop Express

To be clear: No, it's not even close to what you'll get with the full version of Photoshop on your computer but Adobe's Express mobile app is nothing to sneeze at, especially at the low, low price of zero. Editing features include everything from the basics, such as cropping, straightening, rotating, and flipping photos to red-eye removal. There's also a one-touch Auto-Fix and slider controls for color, clarity, contrast, exposure, highlights, shadows, temperature, tint, and vibrancy. If you're in too much of a rush to mess with all that, there are 20 fun, one-touch filters that are pleasing, plus 15 border and frame options for when you're ready to print. [Free; Android and iOS]