1. San Diego Zoo Membership
When you sign up for a San Diego Zoo as an Diamond Member you get 4 free tickets. 2 - for the Zoo and 2 for the Wild Animal Park if you sign up as a Diamond member. They also have the option of Member Plus-one. This means that the primary member can get anyone in at one time. So 4 people can get in to each location (Zoo and Wild Animal Park) in for the price of one membership. Usually we pay $99 a year for a membership. If your going to the WAP a lot buy parking as it is not free like the Zoo.
2. Sea World Annual Pass
Right now in 2010 Sea World has a special where you can "pay for a day get a year free." This means that the second year annual pass is free with a ticket purchase this year. Sea World
3. Balboa Park Museums
Every Tuesday is Free day. The first Tuesday of every month is free day for some of the main museums and Science Center. Just Google "balboa park free tuesday" and you will see the calendar. Residents of San Diego must show ID to get in on these days. This is still a great bargain and Balboa Park is a fun place to take photos. Take a walk along El Prado on a sunny day and you will see lots of places to take pictures.
4. Beach and Embarcadero
If all you do is go to La Jolla shore and then walk along the Embarcadero at sunset you will have a great day. The Embarcadero has some great sea food restaurants and leads into the Gas Lamp district. You can also visit Sea Port Village for some treats and shopping.