How much entrance?

Since you are here, you have internet. Google San Diego zoo and look at their different packages. I think the best bargain is the membership. Cost is twice the zoo price, but you get unlimited entrance to zoo and safari park for a year. And FREE parking at the park. Membership includes 4 single use guest passes for you to take friends to zoo or park for free. If your intent is just one visit, stop by Vons, the sometimes sell two for one tickets.

You can find discounts on line. I used city pass.