When the first Wal*Mart came to Miami-Dade County, they made you show your receipt to a guy at the door when you left. Home Depot and Sav-A Lot have been doing this forever, but now there are 10 Wal*Marts in the County and they no longer check.
I am assuming that they were adjusting their prices to the new environment. Now that the know what the percentage of "shrinkage" there is, they are charging us more and no longer need to check.
Wal*Mart is often cheaper, sometimes a LOT cheaper, but there are several things they charge more for. Oatmeal and peanut butter cups are cheaper at Sav-A-Lot, even the store brands. They have several prices for batteries and sodas: the more convenient the location, the more you pay.
Wal*Mart is successful because they have a handle on their business. There used to be a discount chain here called Zayre's, and they did a lot of business, but they just didn't seem to understand anything: their employees didn't know anything about the merchandise or even where to find it. There was always merchandise scattered all over the place, and most of the time, the price and the shelf and the price on the checkout did not match up.
Once I picked up a tool set with the price of $19.99 on it,printed on the package and it rang up for $4.00 more. The cashier told the manager and he refused to sell it for $19.99. "I don't know why that price is printed on it, but the checkout says $24.99, and that's what we have to sell it for, take it or leave it." So I left it. Hell, I didn't change the price, and it wasn't even that big a bargain.
Wal*Mart charges more in some towns than others, but they don't screw up like that.
Zayres sold out to some other chain that was even more disorganized and they went broke in six months.