During the last month we met personally with three very successful Florida Restaurant and Lodging association members who operate QSR, casual dining, and fine dining restaurants.
While I could list many factors for their success, one common characteristic in all three what that they weren't the least expensive dining choice in their area and two even admitted their customers paid a bit of a premium to eat at their restaurants.
These operators realize that while people want a good deal, price is rarely the number one criteria people use to choose a restaurant. After customers leave, they will rarely remember exactly what they spent, but they WILL remember whether they liked it or not.
Instead of competing on price, the restaurants we visited demonstrated an almost fanatical commitment to delivering high quality food in a friendly, courteous manner to each and every guest.
No matter what you charge, someone can always charge less either because they're more efficient or because they don't have a clue what they're doing.
Focus on being good, not cheap.