Why pick just one? One of the greatest deals in the nation, the National Parks Service offers a National Parks Pass. As of 2009 this pass cost $80 and provided unlimited access to every national park. Everything from Yellowstone to the Grand Canyon and even historical sites like Gettysburg are all accessible using the parks pass. Parks offer a remarkable variety of sights and experiences, including whitewater rafting, geysers, bird watching, hiking, camping and mountain biking. On one pass you can experience both the wildflower fields of Shenandoah in Virginia and the redwood forests of California. The pass is valid for a whole year, so you can hit several on an epic tour or spread out several visits over the year.
Looking for a tropical trip where your money will stretch further than in Florida or the Caribbean? Consider Belize. Plane tickets are likely to be the most expensive part of your trip. Check flight aggregators such as kayak.com for deals, and make sure to pack light to avoid additional fees. Belize has all the features people expect from more expensive destinations: beautiful terrain, pristine beaches and great food, without the higher prices found in Hawaii or Mexican tourist destinations.
The District of Columbia is a remarkable city, serving as both our national capital and a living memorial of many aspects of American history. Cheaper than going to a resort town or a more exotic vacation destination, Washington, D.C., is full of remarkable sights, many cheap and even more free. Check out the memorials or the original Constitution in the National Archives. Of course, there are also the Smithsonian Museums, which have something for every member of the family, from dinosaurs to spaceships. Some specific sites to check out include the holocaust memorial, the Library of Congress, the Reflection Pool, the U.S. Capitol and the National Gallery.
Las Vegas may have a reputation as an adults-only hedonist paradise, but the city does a lot to attract families. Rampant competition and the desire to attract gambling customers means that Las Vegas has some of the cheapest resort-town hotel prices in the country. This same competition for your attention means cheap, high-profile stage shows and food at a great value. As long as you don't indulge in Vegas's alluring vices you can actually save quite a bit of money, all while seeing great family acts like Penn & Teller, the fountains at the Bellagio and the famous pirates of Treasure Island.