I know Google Play allows refunds within a window (it's usually 15 minutes but I'm hearing now it's as long as 2 hours).
Take note that PS Touch is not *quite* as powerful as the desktop version (for obvious reasons). Some things are done a tad differently. (e.g., There aren't any adjustment masks or layer masks but you're certainly allowed to make a duplicate of a layer and work on that and blend it with layers above or below using the various tools.)
It has the layers paradigm down pat and it's more powerful than those goofy "image editors" that just let you add captions or change colors to make the image look like a Polaroid.