You've probably heard it said that the best things in life are free. When it comes to travel, some of the best things require an admission fee. But don't assume that free things to do are not worth working into your itinerary. In fact, some of the very best experiences require no fee: a visit to the Smithsonian, a drive along the rugged California coast or a weekend in Great Smoky Mountains National Park, among many others. Take a look at these stories, which offer tips on how to experience something of great travel value at no cost.

Mark Kahler, licensed to About.comYou don't want to pay for a business-class or first-class seat, but wouldn't it be nice to sit in one anyway? Sometimes, airlines will upgrade their passengers if those better seats are available. Obtaining such a free airline upgrade is not easy, and there is no surefire way of landing this privilege. But there are strategies that can improve the long odds. Take a look at some tips for landing a free airline upgrade.

Mark Kahler, licensed to About.comSometimes hotels will upgrade their guests to a nicer room than the reservation dictates. This free hotel upgrade can add significant value to a budget trip. It is not something that comes easily, but for those who learn to ask the right way it is possible. It's important to know the tips can that lead to a free hotel room upgrade. The first piece of advice: know when and how often to ask for the upgrade during the booking process.

Mark Kahler, licensed to About.comThere are days when you can visit certain museums free of charge. There are also museums that charge no admission fees at any time. This list of
8 free museums includes the world-famous British Museum in London and the Smithsonian in Washington, D.C. Some of these institutions will charge for admission to a special event or exhibition, but day-to-day visits do not involve spending anything other than time.

Mark Kahler, licensed to About.comAirline business models call for overbooking of flights. Each has an elaborate formula designed to balance out the no-shows or last-minute cancellations with fully loaded aircraft upon departure. Naturally, the formula fails to do so on occasion, prompting airlines to offer
free air travel incentives to budget travelers willing to be bumped from their ticketed flight. Find out how you can earn free travel vouchers by simply waiting for the next flight out of the gate.

Mark Kahler, licensed to About.comAlas, some of the finest drives in the world involve paying an admission fee or toll. It can be argued that in most cases, these expenditures are worthwhile. But how great is it to travel some of the world's most scenic highways without stopping at a toll booth?
Free scenic drives add value to any budget travel itinerary. Try to work in at least one as you plan your next adventure.

Mark Kahler, licensed to About.comLet's face it: if you fail to do some careful planning, travel in Europe can be quite expensive. But every day and each itinerary can be enhanced by adding some
free things to do in Europe. For example, did you know on of the very finest views in Paris can be viewed free of charge? The same is true for a walk through the Roman Forum or Westminster Abbey. Make your plans for free things to do in Europe.

Chip Somodevilla/Getty ImagesNew York City offers some experiences that are unique and absolutely free. For example, it costs nothing to cross the Brooklyn Bridge on foot or to take the Staten Island Ferry and enjoy views of the Statue of Liberty and Lower Manhattan. You won't be able to do everything in
New York for free, but if you work a few of these free experiences into your itinerary, you'll save money without sacrificing a memorable visit.

Mark Kahler, licensed to About.comThere are at least eight U.S. national parks that can be visited without an admission charge every day of the year. Some are convenient and popular; others are distant and expensive (but rewarding) to reach. Even in these free-admission parks, there will still be fees for camping and other services. Find out how you can visit a U.S. national park without paying a penny in admission fees.