Hyvee has a policy that if they ring up the wrong price for an item that you get the item for free. I know this is more of a "how to be cheap" post and not really a deal - but most people don't know this.
They used to just take the item off when it was rung up incorrectly. Now, I have to remind them of their policy (they must not like giving away food....what?!). The manager usually looks at me like she wants to kill me and then I smile at her, knowing that the 100 other people ahead of me just paid $2 extra for the item so I'm doing a favor for all the rest of the shoppers who come after me.