On the weekends of June 20, July 18, and August 15, the National Park Service will offer free admission at more than 100 national parks. That's including Yosemite (usual fee: $20), Yellowstone (usual fee: $25), and Acadia (usual summer fee: $20).
Adding to the deal, National Park Service concessioner Aramark is offering deals on tours and accommodations at many national parks. For example, on the free weekends at Lake Powell National Recreation Area, you can buy one ticket and get a second half off for the full-day Rainbow Bridge cruise. At Shenandoah National Park, guests who book a Saturday stay can reserve Sunday night for 50 percent off.
There are more ways to save at parks around the country. SmarterTravel's Josh Roberts recently rounded up summer savings at top national parks in a great photo gallery, and Kate Hamman and Carl Unger featured camping among their picks for top cheap ways to travel this summer.
Now if you'll excuse me, I've got an increasingly affordable camping trip to plan.