Five Claps - Travel and local guide based on the social recommendations
JetRadar - Compare flights from hundreds of airlines & travel agencies
TravelBud - Connect with travelers, whether you are local or traveling
Skyscanner - Skyscanner.com compares over 1000 airlines to find you the cheapest airfares, fast.
Party with a Local - Party with a Local is a free app that connects travelers with locals that want to party.
FareUpThere - Earn rewards for your feedback on flights