Free
If you visit the Grand Canyon, you can do all sorts of fun things.
You can sit on a mule and ride from the rim to the bottom. You can paddle down the Colorado River on a raft. You can hike, bike, snowshoe, and cross-country ski. You can take a tour bus, a jeep tour, or an automobile tour. You can tour the canyon in an antique railroad car. Or you can even take a tourist flight and sit back and enjoy the views as you learn about the canyon.