Back in the ’60s, the Diggers—the group that essentially founded the hippie movement in Haight-Ashbury—pioneered an entire economy built on barter. One of their most inspired innovations was the Free Store in which all items were there for the taking. Times have changed, but even in the home of $4 toast and $7 coffee you can still have a great time without reaching for your wallet. Simply strolling the streets is one of the best things to do in San Francisco—and it's free. Even the most jaded locals find themselves gasping on hilltops—and not just because of the climb. In the Mission, exterior walls provide a gritty outdoor canvas for intricate murals by world-renowned artists. Urban street art gives way to urbane galleries in Potrero Hill, where a cluster of galleries makes it a convenient area for a contemporary-art crawl. Or take a hike: Within the Golden Gate National Recreation Area (GGNRA) more than 115 miles of trails skirt its dramatic coastlines. Below are our top choices for the best free attractions, events and museums in the city.