Perfect365 is an image editing app that allows you to automatically filter any facial photo or apply specific makeup to it. It's not a manual makeup app -- you can't go through and add specific amounts of blush or foundation to someone's face. It's all filtered, but the effects are very well done and because they match the skin tone based on the image, the resulting images look quite good.
When you open Perfect365 for the first time, you are asked to take a photo or load one from your camera. Because of how the app lines up the face, it's recommended that you take new photos just for this app. It will then match the key points on your face and create images for you to edit. In the editing screen you can tap any of the makeup filters and it will automatically lighten, darken, or add makeup to the face of the subject. In testing, the results were often impressive and occasionally funny, but always accurate. You can then export the images when done and share them with friends. The interface is a bit elementary, but it works well considering the number of options you'll have to dig through, and everything appears to be unlocked in the free version.
While not as powerful as some of the free makeup apps provided by the major cosmetic companies, this app is free, doesn't require a log-in, and works well for a variety of applications -- making it a good free download option for anyone that wants to test out different looks, digitally.