I thought if you wanted to search for fare prices from one city for a specific date to anywhere under a specific price Momondo, Google Flights or Skyscanner are the stuff to use but they don't work on my Android phone. Are there any apps to have this search option for Android?
I don't think you need a standalone app for this.
You can use Adioso for open ended searches and it has a responsive design that will work on your device. The only part that it won't do is restrict the search to be under a certain price.
You can add the site as a bookmark to your home screen and it will not really be much different to what a standalone app could offer.
You could use wander for that, it's a travel destination search engine, you enter budget & dates, and you receive destinations that fits within that...