Fare-ly Great Site
Farecast is a travel site that offers very different information for those traveling by air. You can still search fares as with most sites, but their best feature is their airfare predictions. If you have any flexibility in your travel, you will want to take a look at what the chart looks like for airfares. Amazingly, the search I put in showed that tickets would fluctuate as much as several hundred dollars within a few days! Recommend this one to your library patrons who struggle with larger travel sites to find the fares they are looking for. The graphs make it so much easier to understand!