SFO has an excellent choice to buy food to take on board. There is a Deli that makes custom sandwiches at very reasonable prices right at the CO gate area.

Prices are around $6 for sandwiches with choice of bread, meat, etc. They also have salads - $5-6 and other side dish items. The place appears to be very popular with CO travelers. Looks like they have significantly increased their staff since the CO BOB started.

I was going to do BOB, but decided to go with the Deli. Others on the CO flight indicated they tried the CO BOB and it wasn't very good.