Traveling? Check out 3 small dot.coms for best airfares

The big-three online travel agencies — Expedia, Travelocity and Orbitz — are the first places to turn when you're looking for good airfares. But the big three don't always find the bargains, and they don't tell you whether the ticket price is likely to be lower now or later.

Three less well-known travel dot-coms address these issues and deserve a slot among your bookmarks. (The sites don't sell tickets themselves but send you to airline Web sites and online agencies for booking.)

• FareCompare.com. Plug in your proposed itinerary at FareCompare.com, and the site reveals the lowest fares that day, along with a chart — similar to a stock-price chart — of the recent trend in fares. Compare today's lowest fare for your route with the lowest average fares for, say, the past month. If today's fare is near the recent low, it's probably a good time to buy. The site updates its fares shortly after 10 a.m., 12:30 p.m. and 3 p.m. Eastern time.

For example, we recently shopped for round-trip tickets between Atlanta and San Francisco 30 days before the travel date. The lowest fare was $288. FareCompare said that the average advance-purchase fare for similar sales during the past few months was about $288, so this was a solid deal.

• Airfarewatchdog.com. If a fare doesn't stack up well on FareCompare, you may want to jump to Airfarewatchdog, which scours the travel databases for domestic and international flights and then fetches fare specials that FareCompare and others might overlook. Use it when you're ready to buy tickets right away. Your trip can be as little as three weeks or as long as a year away.

The site recently quoted, on 21 days' notice, a round-trip ticket from Los Angeles to Lexington, Ky., for $178 (before taxes), when fares during the previous month had averaged $487. We couldn't track down the $178 deal on our own, but Airfarewatchdog spotted it at the Web travel agency CheapAir.com.

• Farecast.com. When you want to know whether an even better deal is around the corner, you may be able to find the answer at Farecast. The site predicts whether fares on a route will go up or down in the near future, to help you decide when you should buy your ticket.

To make its forecasts, Farecast analyzes past fare trends in airline databases and other factors affecting price. As of this writing, it predicts fares only between Boston and Seattle. But the site plans to expand to cover routes between most major U.S. cities by year-end.