First, the price is right. This is a free app for both iPhone and the other ones. The idea is to give you some idea of what a color will look like on your wall, or in a listing. It takes into account the lighting, which can really be tricky. Having made a few majorly awful choices in paint colors, I'm looking forward to using this on my own house. I used it in a listing to narrow down the choices, then got a sample color just in case.