It is frequently the case that Tom Thumb advertises a sale, but the item is not marked down at the register.
Because I have lived nearby, I have shopped at 2 different Tom Thumb stores for the past 20 years. This problem has existed all that time. Since I first noticed it I have always read my receipt. At one time I roughly calculated that 5% of my grocery bill was overcharges on sale items. In that time there has never been an error in my favor. I shop twice a week and an error like this occurs approximately every other time. Last week I was overcharged $17 on a $120 bill.
Every time this happens I have try to remember what the price of each item was, then I have to read the receipt and make sure the checkout amount is correct. If I have time, I sometimes go back to the aisle to double check the price. It is absolutely not possible to follow this on the screen at checkout, what with their little dots and codes and mark downs at the end. This is really hard to do.
After you checkout, you have to read the receipt, then determine whether you have been overcharged. If so, you have to go stand in another line at the office. They always give me my money back, but it adds 30 minutes to my grocery shopping while my frozen food melts.
Tom Thumb has a new program called "Just For U". You 'add' coupons on your computer. I used it for the second time, today. Both times it failed. I was charged full price for the item. I asked what I might have been doing wrong and was told that there might be a "glitch" in the system.
My concern is this: Hardly anybody checks their grocery bill. Even if they did it's hard to remember the prices of all that stuff. If these "glitches" are as widespread as my experience, that represents a lot of money.
Check you grocery bill, especially on sale items.