Check out the allears.net website. They have menus complete with price lists that I found helpful when my 5yr old and I went. We spent $200 in food and a few small souvenirs over 4 full days at the parks and the 1/2 day on arrival and departure. We stayed at a Value resort, and that included our room, park passes, pickup and drop off at the airport, and transportation between parks. I think you get your best bang for your buck by staying on site.
We brought snacks into the parks from home, and brought some food from the value resort in with us well. Disney allows you to bring in food and drinks, just nothing alcoholic, and I think nothing with a straw into Animal Kingdom. I hope this helps.

If you live in Cali, then it should be around 6,000- 8,000 dollars for the weekend. You can get deals on the allears.net website.