6 hidden travel costs

Booking fees. Nearly every major carrier now charges a 'convenience fee' for booking in-person or over the phone, ranging from $5 to $45 per ticket. The easiest solution to avoid the fee: book online. Many online travel agencies have eliminated their booking fees (at least temporarily), so you can save even if you don't book directly with the airline. Note: Even if you book online, airlines often charge a fee for any itinerary changes made over the phone. If you're in any doubt about the airline's policy, ask the representative at the start of the conversation if you will be charged and the amount. (See Up, up and away with airline fees.)

Other considerations:

-- Frequent-flier fees. Before you get too excited about those frequent-flier points, keep in mind that airlines often tack on extra fees for taxes and baggage. These fees can range from $40 to $150 a ticket, depending on the carrier and destination – so make sure to read the fine print. The best way to avoid these fees is to book as far ahead of time as possible. For instance: In addition to a $25 ticket 'processing' fee on every flight, United Airlines charges $75 for tickets bought seven to 20 days before the flight, and $100 for tickets bought six or fewer days before departure.

-- Online booking restrictions. Some of the best online deals come with heavy restrictions. Make sure you know the details such as how much extra you'll have to pay for luggage or the number of beds in the room.