Anyone who knows me well knows that I like cheap and free things to do with the family.
1) Golden Gate Bridge. This is a favorite among tourists for many reasons. One of those reasons is the fact that it is one landmark that belongs only to San Francisco. It is uniquely a part of this city and represents, for many, your entire trip. Another reason is that there are so many ways to get there. I recommend walking and if you're up for it, try one of the guided walking tours-this will provide valuable background information about the bridge as well as insuring that you don't get lost on the way. 
2) Golden Gate Park. This park is larger than New York's Central Park and in my opinion equally grand. There is so much to do and see in Golden Gate Park that you could spend a good portion of your vacation here alone.
3) Cable Car Museum. Kids of all ages will find this museum interesting, especially big and little boys. This museum definitely offers a great deal of education and excitement for the family. In addition to learning about these neat cable cars which have become a trademark of San Francisco transportation. This is one museum I would pay to go to, the fact that it is free is a bonus that I can't resist and the primary reason it is on this particular top ten list
4) Walking Tours of San Francisco. These free walking tours are not only entertaining; they are also very informative as well. Learn about the history of the neighborhoods that this city is famous for as well as the great people who rebuilt a grand city, literally from the ashes of what it once was and made it even better. San Francisco has a wonderful story to tell and these guides narrate it wonderfully.
5) San Francisco Fire Department Museum. For the big kid in all of us that wanted to grow up to be a fire fighter, this museum takes the cake. Not only does it provide great historical references and artifacts but it is also really cool! I can think of no greater compliment to give a museum than that. This one, even your children will enjoy and beg to go back again and again.
