There are lots of free things to do in San Diego, but one of our favorites is walking along the beachfront path at sunset. The views are stunning and it's an easy walk from downtown San Diego. Head out early enough and grab dinner at one of the many restaurants along this route before heading back home. There are plenty of things to do in San Diego that don't cost a dime. You can enjoy the city's beaches, which are some of the finest in all of California. There are also plenty of museums and parks where you can get some fresh air and enjoy nature without spending any money. If you're looking for something fun to do together on a budget, check out Balboa Park or Mission Beach. Both places offer tons of activities at no charge, including street performers and live music concerts.