I've noticed some of this too, and a bigger trend I've noticed lately is that buying bigger quantities isn't always cheaper anymore. Take Pepsi for example. At several of our local stores it is cheaper per ounce to buy the 1.25l bottles (and buy more of them) than it is to buy the 2 liter bottles when you break it down to a per ounce price. Also, Food Lion is bad about jacking up prices before Buy one get one free sales. They'll have a BOGO offer where you get the second one free, but raise the price for one to nearly the same price or higher than it would be to just buy two of the item at another store outright.
Another big trap people fall for are Dollar General and Dollar Tree. Typically their quantities are smaller, and priced higher per ounce than what you would see at Wal-Mart for example. I saw someone in line the last time I was in Dollar Tree with 6 items at $1.50 each. Four of them could've been had for less than $1 at Wal-Mart. The crazier thing is the Dollar Tree is in a shopping strip mall located in the Wal-Mart parking lot.
