$5 lunch specials + Monday night specials at Hungry Bear Fullerton
Hungry Bear Restaurant (not to be confused with the one inside Disneyland) has been in Fullerton, CA since 1973. They have $5 lunch specials from Monday to Friday, and occassionally even on weekends.
They also have daily specials (my favorite is their Corned Beef & Cabbage on Sundays for just $9.95). On Mondays they have select menu items for half off.
For more information, click here. It is not a big restaurant, and a lot of seniors frequent here, but the food is good and comforting.
Hungry Bear is located at 2219 N Harbor Blvd, Fullerton (cross street is Bastenchury, near St. Jude's hospital).