I do believe any of the Jimenez grocery stores will carry it in a little box in one of the aisles. Just a starting point for you. I'd bet there are quite a few other grocers that will carry it, but Jimenez locales are pretty plentiful.
Another good bet would be Tony's Finer Foods locations. Fullerton and Central PK would be a good bet for Tony's. If you give an approximate area, maybe a store could be pinpointed? It is available city wide if you know the right spot.
We cannot be friends if you do not know the difference between Mayo and Miracle Whip.