Probably some of this stuff is common sense...
Make sure that you eat lunch--not dinner--at the expensive restaurants, because lunch menus are usually less expensive than dinner menus.
Rancho del Zocalo in Frontierland has big portions, for a relatively small price, and you can order a la cart even though it's not listed on the menu.
A lot of people eat a large breakfast off-site, and try to avoid eating in the park during the day. Also, if your hotel offers a free continental breakfast, it might save you some money on food.
Good neighbor hotels should offer tickets for less than the gate price. (And there are a fair number of off-site hotels which are actually a shorter walk to the gate than the Disney resort hotels.) There are quite a few hotels recommended on this board which are cheap, but nice hotels. I've heard good things about HoJo Anaheim, and I've stayed at the Ramada Maingate for fairly inexpensive and they were a good hotel, also.
One thing that my family does--keep in mind that my family refuses to leave the parks to eat off-site--is to plan out what restaurants we will eat what meal at. That way, we know in advance what is in the budget, and we don't have to walk around looking at menus. We use a park guidebook to see how expensive the restaurants are, but I've also found menus on-line.
The tortilla factory in DCA has free tortillas, which are warm from being baked right there. They're a GREAT light snack. There's another tour there that offers free food, but I can't remember it because we kept going back for free tortillas.
Okay, looking back, this is probably nowhere near what you're trying to find out, but just in case, here it is.
Hi 
"Montana Minnies"
