Google bought out Quest Visual to use it's functionality in it's Google Translate.

"As a thank you to everybody who supported us on our journey, we've made both the app and the language packs free to download for a limited time while we transition to Google."

The app uses the camera and translates whatever text is displayed right on top.

The app is usually free with an erase text or reverse text as demo, but each language pack would cost $4.99

See the world in your language: instantly translate printed words using your built-in video camera, in real time! (PLEASE NOTE: language packs must be purchased separately from within the app.)