You've probably clipped cents-off coupons from your Sunday newspaper to buy stuff like toothpaste, but did you know that you can also use "coupon" deals to cut the cost of your next vacation?

Time to get on the promo code and "members only" bandwagon, frugal flyers. Recently, United Vacations offered a coupon code deal with $700 off vacation packages from the US to Canada, for two people traveling together. Turns out there was some kind of glitch, and it also worked for one person traveling alone. So you could have flown from San Francisco to Vancouver and stayed three nights in a four-star hotel, including air fare and all taxes, for about $98.

A similar deal on packages to the Bahamas from Florida recently worked out to--sit down for this--$0, including tax. And airfarewatchdog.com staffers have been able to combine those crazy 9 cent or $1 fares on Spirit Airlines with their frequent "50FF" and "35OFF" promo codes to get $50 or $35 off the total fare, again eliminating not just the airfare but also the taxes. Nothing beats flying for nothing.

So how do you get these deals? It's pretty easy, actually, but you're going to be getting a lot for email in your in box. When you sign up for the airlines' email newsletters and frequent flyer programs, they reward you by sending out special deals that only members can use. Often, they're in the form of a promo code that you plug into the airline's web site booking engine. Sometimes these deals are generic, such as Spirit's 50OFF deals, but in other instances they're individually generated so that only you can use them.

Oddly, airlines don't always make it easy to find their newsletter and frequent flyer sign up links. So that's why airfarewatchdog has put them all in two handy places: one for international airlines and one for domestic carriers.

As we said, yes, you'll get more email. But the savings will be well worth it.