If you are looking for something free to do while visiting San Diego, why not try out the Spruce Street Suspension Bridge? It is located in the Bankers Hill neighborhood on West Spruce Street. It is a bit hidden but you will find the entrance just look for it at the end of the street.
The bridge was built in 1912 to connect the 2 neighborhoods. It is 375 feet across and has a drop of 70 feet into Sessions Canyon. It is not for the faint of heart. It does rock some as you walk across. I am not a huge fan of heights so I didn’t love it but it is totally worth checking out!