1. Time it right. Set your clock: The best time to snag a cheap flight is Tuesday at 3 p.m. EST, according to a study of airfares conducted by farecompare.com. An airline will typically kick off a sale late on Monday, and other companies will join in to stay competitive -- and all those reductions hit the reservation systems on Tuesday afternoon, says Rick Seaney, CEO of FareCompare. But act quickly: They're usually off the grid by Thursday morning.
2. Search near and far. Even if you're flying within the U.S., check any travel site's international counterpart, because you may find lower prices not listed on its domestic version, says travel expert Lori Rothschild Ansaldi. Why? Fewer people are looking for those flights, so airlines offer more enticing fares. At press time, the best rate for a direct round-trip flight from Austin to L.A. on kayak.com was $298, but Spain's kayak.es listed it for $244. (Currency conversion sites like xe.com make the math a little easier.)
3. Get a frugal fill-up. Gas is how much?! Instead of driving around looking for the cheapest gallon, download GasBuddy, a free app that senses your location and shows you a map of the nearest gas stations and their prices. You can also get lowest-price tips from other users or tank up on good karma by entering your own on-the-road reporting.
4. Spend the night for free. Couchsurfing.org is an online community that lets travelers link up with hosts all over the world who have a guesthouse, spare bedroom or sofa to share...for free! Its millions of members, who may be traveling alone or with families, leave copious feedback on their stays, so you can research a good match for your needs.
5. Ride like a local. Don't toss your train-ticket stub: Many metropolitan public transportation systems will honor Amtrak receipts for free rides through their city, says Rothschild Ansaldi. For instance, show your stub on Philadelphia's SEPTA and you can travel to its Center City stations; and in Portland, ME, hop a same-day ride to popular destinations like the Arts District. Check online or stop at the info booth to ask if your city is on board.
6. Get the inside scoop. Use social media to be, well, more social! On Facebook and Twitter, "like" and "follow" anything associated with your destination to become privy to fans-only offers and news, says travel expert Valarie D'Elia, creator of travelwithval.com. She also suggests staying connected once you get to your new city: "Many restaurants, spas and museums post passwords for same-day discounts, or trivia questions where correct answers win you free tickets to events happening that week," she says. Recently, the Ogden Museum in New Orleans offered free entry to Twitter followers who said "blues rap" when they arrived.
7. Fly first-class for less. When searching for flights, check out discounted first-class rates called Y-Ups. The airlines' best-kept secret, these are unsold first-class seats that are generally available at the last minute. Very few of us bother to look at premium tickets when we shop online -- the search default is usually "coach" -- so we never see these lower prices. (Psst: Y-Ups often begin with the code letter "Y.") The level of the discounts can vary, and they're usually just for one-way tickets, but you could end up grabbing a luxurious seat for the price of a regular coach trip.