How much would you feel comfortable spending at dinner out?
No special occasion involved, just imagine you wanted to go and sit down in a restaurant to be served on a Tuesday-Thursday night. Include alcohol (if applicable) to your tab, but do not include tip (to account for all of our European posters). Imagine you're only paying for yourself in this situation.
If you want, give us some more detail on where you'd go/what you'd eat.
When I go out by myself to eat, I try to keep the total cost under twenty bucks. I don't drink alcohol, so I don't have to worry about that. My favorite local place is "Archie Moore's" in Fairfield, CT. It's a bar and American food kind of place....very popular, especially among the college crowd in town. They make some mean desserts, too.