I really like how Flight Fox does this in showing sample trips. It allows you to see the sort of savings they've been able to find.
Am I missing something and this is a per-person cost? That surely wouldn't gel with the statement about it being a more affordable option for flights shorter than 300 miles?
 Looking further down, it turns out that all their graphs are horrific.
featuring some real people http://bit.ly/Wo7h8T
stock photography has its place...but not beside this paragraph: "The idea of trusting a broker with your flight is crazy nowadays. Before you book your flight you can read real reviews from verified customers. Never again will you have to worry about whether or not you're getting a good deal, or will have an excellent flight!"