If you want to compare airfares easily online, one new tool is offered by FareCompare.com. Their newest feature lets you track the lowest fare prices between cities, and rates each fare from 0 to 4 stars. Except with this ratings system, the stars are objective: Only deals that are close to or better than the all-time low price can rate 4 stars. It’s a simple way to get some perspective when you’re searching for airfares.

Then there’s Farecast.com . Their Farecast Deals are reportedly the first “scientific” set of airfare deals. They are generated only when fares reach certain historic low prices, as calculated by their airfare prediction engine, which has literally billions of prices on file. So theoretically, the only deals available would really live up to their name. But how accurate is it? An independent audit by Navigent found that over a period of three months, 74.5% of its predictions were ultimately found to be correct. Also, the analysis found that travelers saved an average of $50 per roundtrip ticket using the site, if they adhered to the site’s guidelines and followed its predictions.