You can often find a great deal, especially at short notice, if you're willing to buy without knowing key travel details such as your airline or exact flight times. Opaque pricing sites like Hotwire and priceline offer deals of this kind.

Hotwire has two options: its traditional packages, as well as "Weekender" deals, for travel in the next 14 days. Traditional packages are available to destinations across North America and the Caribbean. And, unlike when you shop for accommodations-only with Hotwire, you'll know the name of your hotel before you buy a package. For travelers who are shopping at the last-minute, Hotwire's "Weekender" option may be a good one, as deals are available for only the coming weekend or the following one. Again, although you won't know your exact flight details, you can pick your hotel from a list of choices.

Once you enter your itinerary and specify your travel preferences, Hotwire will offer you a complete price, including taxes and fees. However, you won't know your airline or exact flight times until you agree to book. You have two hours before the fare expires, and you can't run the same search again for 48 hours if you pass on the original deal.

And while priceline allows you to bid whatever you want for airfare, hotel, or car rentals booked by themselves, its package offerings are similar to Hotwire in that they provide you with the available prices and hotel names before you book. Destinations include those throughout the U.S., Canada, the Caribbean, and select European cities. The only thing you won't know is your exact flight or its timing. Again, like Hotwire, priceline now has a "Weekend Getaway" option, though the latter has no restrictions on when you travel, so it's essentially the same as priceline's regular package offers.

Also, note that with both sites, one-way travel is not available, you won't earn frequent flyer miles for your travel, and your bookings are entirely nonrefundable and nonchangeable.