FareUpThere - Earn rewards for your feedback on flights
Gopher - Better hotel deals automatically, every time + cash back
Eighty App - Convenient travel wishlist app with booking alerts
Earny.co - Win prizes on Amazon purchases
Skyscanner - Skyscanner.com compares over 1000 airlines to find you the cheapest airfares, fast.
HotelTonight Escape - The best getaway deals for tonight (or the weekend)