I am in-charge of the travel desk in my organization. I have been asked to slash travel costs as a cost cutting measure owing to the recession. I have to book tickets to various destinations for our executives who have to travel a lot. Sometimes we end up paying very high air fares even for short distances. I need help from a travel search tool so that I can cut down the budget of my company.

It is an updated site with low cost carriers and major airlines both listed in it. You can find an optimum route for yourself mapping your preferred route. This websites can also be very deceiving and show you a great price and then you get to the purchase page and the fare is all of a sudden no longer available. This websites are for the most part accessing the airlines direct availability anyways.
You may score some cheap seats with price line, but be aware as someone else said you have to give your credit card ahead of time before you even know what you are getting.