Fast food isn't a bad idea for the first date. A public place with relatively cheap eats. You could always go dutch, but it's understandable that you may not want to. 'Course McDonnald's doesn't offer much for entertainment. Maybe a nice little local cafe? Probably cheap food and not as artery clogging, if you or she are health conscious. A "walk in the park" is not a bad idea. You could point out that you're getting exercise, and there'd be no shortage of scenery to comment on when you hit a lull in the conversation. Any museums or art exhibits around? Mini golf or cheap bowling? Animal shelters you could volunteer at for a day or just visit to do some petting?

Maybe an ice cream parlor? Make sure she knows what you're planning to consume before you go out so she isn't on an empty stomach. This way you can eat something good together, chit chat, keep it from being drawn out, and get off pretty cheap in the end. Best of luck, whatever you do.