This was many years ago. There was a store named Jamesway in New Jersey. Mobil 1 was on sale for $3.33 a quart. But in the store, the Mobil 1 was in six packs. So, I bought one, expecting the price to come up as $19.98. Instead, it came up as $3.33 for the entire six pack. I told the check out person that the price was an error, but she insisted "OUR REGISTERS ARE NEVER WRONG" So, I paid the $3.33 for six quarts. Then, given that the registers are "never wrong", I went back in and bought out all the Mobil 1 on the shelf, about a dozen more six packs. Went back to the same register, paid $3.33 a six pack again, and strolled out the door to my car and left. And paid cash, so my name was not traceable to the sale.
I figured, with that level of arrogance, I deserved the bargain.
And, coincidentally, the store went out of business about three months later.
www.milesoil.us
plus there were mail-in rebates!
