Just to warn you…dollar general is not an all for $1 store.
I knew that. But as long as we are warning people of things to look out for, I came across a YouTube video the other night where Dollar General has been sued in a number of states for jacking up their prices in the computer checkout register - but leaving lower prices displayed on the shelf.
Just one example...
I don't think it's fair to single just Dollar General out. I have ranted a number of times about WalMart charging higher prices at the register than their display prices.

It happens everywhere. Dear Wife was buying an item at our local big box grocery store that was regular price $9.00, on sale for $5.00. The register rang up the item at $15.00! Well, at that time, she only had a few items in her basket so that price hike stood out immediately. But I wonder how many other people bought that "sale" item as just one of a cart full of goods and paid $15.00 each for that!?
Of course, she complained about the overcharge. The checkout lady sent somebody back to the display to verify the sale price and she did mark it down for us. But - and you all know this - the next person in line with that same item would be charged that $15.00 again because they never correct the sale price in their system.
If you want to save money by purchasing items on sale, just make sure you actually get the sale price. That goes for everyday stuff as well, but I see those "sale" items more often do not ring up at the reduced price.