MOMONDO: THE PERFECT HELP FOR TRAVEL PLANNING
They are free and global travel website & guide that helps you with travel planning! They are a Danish company founded in 2006 and they work globally, allowing users around the world to search and compare prices for flights, car rentals and hotels.
Momondo offers a summary and redirects users to the websites of airlines or travel agencies to complete the purchase.
They also have a very cool blog: MOMONDO: DISCOVER where they have prepared tips and information for all users.