Where it stops, nobody knows

We have one grocery store in our little town. Unfortunately, it's over-priced, poorly stocked, and ineptly managed.
Overcharges are so common that I've pretty much given up on reporting anything less than 5 cents. The $5.00+ overcharges are something else again!
Every time I report an overcharge to the manager, he is very apologetic, gives me a full refund, and promises to speak with the individual responsible for ensuring, "the price at the register matches the price on the shelf". Pfft!
I've tried to monitor the prices at checkout but it's impossible. The scanning process is just too fast. I usually wait until I'm in the parking lot to review the sales slip for accuracy. (Gee, I remember when prices were attached to each item and the checkers would say the prices out loud as they entered each one into the cash register. Maybe it was a little slower, but it was much easier to catch errors.)
One day I noticed a sale tag on an item that was HIGHER than the shelf price. When I brought it to the manager's attention, he looked closely at the shelf price label and said, "The shelf price was put there in 2004! There's no way that's still accurate." So... customers are supposed to read the really really fine print on the shelf price label, find what year it was posted, and guess whether or not it's still accurate?!! Give me a break!
I placed a call to the regional manager yesterday. His secretary told me he would call me back. I'm still waiting.
A long term resident told me yesterday that I shouldn't get my hopes up. He thinks the parent company pulled a shady deal with our city council when they came to town which effectively prevents any other grocery stores from opening within city limits. Consequently, they don't care if we like the service we're getting or not. They are the only game in town!
So, at this point, my choices are these: 1.) Continue shopping locally and keep complaining to the manager. 2.) Drive 12 miles down the highway to the next town and shop there. 3.) File a complaint with the state Attorney General's office.
Considering the cost of gasoline, option #2 is out. I've tried option #1 long enough without results. That leaves option #3. Heh heh heh.
Fasten your seatbelts.