Newsletters are wonderful sources of information about promotions and specials. Newsletters can be especially helpful if you’re planning a vacation and are flexible, since a variety of newsletters including Travelzoo, Shermans, Booking Buddy, and others offer air, hotel, car, cruise and vacation package specials that can save you money. Airlines also offer their own newsletters, accessible from their respective Web sites, but third-party newsletters like those offered by Travelzoo, offer some great deals.

Airline Newsletters: Airline newsletters contain the latest news and deals that pertain to a particular airline. These newsletters inform you of their latest sales, frequent flyer program information, and expansion plans. If you fly on one carrier often, it's a good idea to receive their newsletter to keep you up to date, particularly if you have a frequent flyer account with that carrier. Promotions listed in newsletters are invaluable ways to boost your account, and many of them don't require a flight. The sales listed in these newsletters typically aren't jaw-dropping, but it can't hurt to know about them because they sometimes can save you money.

The Airfare Watchdog: The Watchdog is a deal site in a category of its own. While the Watchdog is talked about more in the ebook, the site offers an extensive list of heavily discounted fares from most major markets across America. The site also has a series of newsletters, the most popular one being the Daily Top 30, which lists the 30 or so fares that the Watchdog's editors like the best. Checking the site often is a great way to find low fares.

Travel Deal Sites: Travelzoo, Shermans, and Booking Buddy all offer a primary newsletter with 20-30 travel deals sent out each week. Companies that offer these deals pay to insert them in these newsletters. Some of these deals are terrific, while others aren’t so hot. Travelzoo also offers another newsletter called a Newsflash, which has offers sent out whenever an advertiser has a deal from a certain market. Often these advertisers are airlines, online travel agencies such as Expedia or Travelocity, or vacation package specialists such as Vacations for Less. Reading these newsletters each week can give you some great ideas for flights or vacation packages, but make sure you compare the price of the package at multiple sites. For example, an airline may sell a package for less through its vacation Web site than the advertiser in the newsletter.

Online Travel Agencies: Sites such as Expedia, Orbitz, and Travelocity also send out their own newsletters, but most of these are filled with mediocre deals that in most cases could be purchased elsewhere for less. The deals featured are of an assorted nature like those found at Travelzoo, Shermans, and Booking Buddy. Site59 (for more info about Site59, see Last Minute Travel) also features their own newsletter that is personalized based on your home airport.

Priceline: Priceline on the other hand, offers an interesting newsletter called Pricebreakers. Pricebreakers has the same types of deals found in an Expedia or Travelzoo newsletter but lists them in order of how soon they will expire. Since the newsletter is currently sent out weekly each Thursday, many of the deals that will soon expire are for travel this weekend, like one might find in a Site59 newsletter, while other deals that expire later are for travel in the coming weeks and months. This gives the newsletter a bit of variety other newsletters lack.