KAYAK Kayak is one of my favorite flight and hotel aggregating sites because it always seems to find me the best deals. The navigation could be a little slicker, but the deals could not possibly be any better, so I'll take it!

TripAdvisor Hotels Flights This is a one stop budget app with info on hotels/hostels, restaurants, night life, and entertainment for cities all over the world. The thing that makes me gravitate towards tripadvisor is the solid number of thorough reviews by other budget minded travelers. The candid photos provided are often also a nice insight into what you're getting yourself into.

TripIt Travel Organizer Free If you're traveling on a budget like me, then you're your own travel agent, and are responsible for being on top of all your flight/train/hotel/hostel details. This app helps keep it all organized and in one place for easy access.

Hotel Finder Lodging can be maddeningly expensive. This is another aggregating app that I like in addition to kayak for finding cheap digs in your chosen city.