Varies wildly around the Atlanta metro area. Most expensive we regularly go to is the VIP theaters (big recliner seats, not as many people, 21+ up only, good beer etc.) in the Regal in Atlantic station. That's something like $21.50 (doesn't matter time of day) each after the online ticketing fee etc.
Cheapest we go to usually is a crappy AMC at the Stonecrest mall that's like $6.50 a matinee.
Honestly, we just don't go often any more and mostly just to the VIP since it's so much nicer and fewer problems with other patrons since being 21+ and pricey helps a lot on that front.
We'd rather spend the extra money to enjoy the few movies a year we feel a need to see in the theater, than cheap out and go the crappy AMC where people are usually noisy, speakers are often have static etc.