Despite the proliferation of low-cost airlines, airfare still remains a significant line item in many sales budgets. The good news is that the Internet has introduced ways for the budget-minded business traveler to find significant savings.

If you can schedule some last-minute meetings, check out your favorite airline's listing of bargain flights. Almost every major airline now lists a grab bag of heavily discounted flights. Recent fares I've found include a $329 round-trip from Los Angeles to Amsterdam and a $39 one-way from Boston to Philadelphia. You can view these special offers by either subscribing to the airline's e-mail alerts or visiting their Web sites for full listings.

Not surprisingly, these bargain tickets do come with a few hitches. Besides being nonrefundable, flights usually require a Saturday-night stay. Taking advantage of these fares can also be difficult since advertised flights are usually not listed until Wednesday and available flights vary from week to week. Moreover, travel is generally restricted to leaving that Friday or Saturday, with a return flight often required on the following Monday or Tuesday.

If last-minute bookings are not an option, consider a bidding site like Priceline.com. With Priceline, you list the desired destination, the days you want to travel, and the price you are willing to pay for a specific round-trip ticket. Within an hour, you'll learn if there is an airline willing to provide travel at that price. What's great about the service is that it's free, doesn't require a Saturday night stay, and allows you to book travel anywhere from two days to six months in advance.

Priceline.com does have its drawbacks, though. Most notably, you can't determine when you will actually be traveling-you need to be flexible enough to travel pretty much any time on your specified days. Also, you must be willing to endure at least one stopover and be open to using any number of airlines. Participation also requires a bit of research; since you can only list a particular trip once, it does require a dose of reality when setting your price. Understandably, frequent flyer miles aren't available either.

Where Priceline relies on airlines willing to undercut their regular fares, TravelBids looks to travel agents willing to take a smaller commission. With their auction process, you directly book a flight with your desired airline. Then you pay $5 to post your reservation, which must be $250 or more in value, and wait for travel agents to indicate how much they are willing to charge for your ticket(s). A minimum discount of 6 percent is guaranteed, or you don't have to use the system.

Although TravelBids does give you the greatest control in scheduling, it does mean that you'll have to spend more time checking out and reserving flights. This time may not be offset by the savings as a $350 flight may only result in $16 in net savings. But the good news is that you can book any class ticket you'd like and can still collect frequent flyer miles.

Quick tips

Travel agencies can save, too. A savvy travel agent may be able to save you some money through ingenious flight routing or alerting you of special promotions. Time is of the essence. Once you've decided on a last-minute ticket offered by an air carrier, make sure to act on it fast. These tickets can go quickly--sometimes in a matter of hours. Confidence required. Be sure that you've investigated pricing thoroughly and are confident about your travel plans before posting your listing. Otherwise you may end up with a charge to your credit card--and a ticket you no longer want.