I will assume you aren't on any meal plan and don't have any discounts.
We found that at many of the counters, we could split meals.
At Pop Century, a $7.19 flatbread sandwich and a $1.29 order of fries could feed both me and my wife. If you don't want the fries they have fruit, small salads, and all kinds of good things. That's $5 a piece. Same as you'd pay at Mickey D's for junk. We found we could split a shrimp noodle bowl if we wanted to also. Now some of the things we really couldn't split. The $6 Pizza's were too small to split. The $6 hotdogs are too small also.
Similarly. Cosmic Ray's half chicken and ribs platter and extra sides could feed two adults and a child for $15. Again, $5 per person.
Another thing you can do is bring some bananas or other fruit with you and eat it for breakfast. Eat it before you go out for the day and it will get you through to lunch.
If you do decide you want a burger, head to Pecos Bills order a double burger and an extra bun. Then pull it apart and you have two burgers for about 8 bux instead of 12. There's a topings bar so you can put on what you want.
http://www.allearsnet.com/menu/menus.htm
There's the menus for everything.
I'm sure others can give you even more tips.... But