In Canada if a poorer person picked an item up at $3, then some rich dude walked behind him and it became $4, legally they would then have to give him the item free because of a price difference on an item under $10. Over $10 dollars you automatically get the lower of the two prices.
Edit: I've been informed it's not a law, but a voluntary act by retailers (screams internally).
Man, egg on my face, I thought it was a law. The way grocery stores are actively turning hostile towards customers we should probably make it a law.
In truth, we should probably nationalize grocery stores, but a more realistic, capitalism driven, "profits before people" approach would be to make it law.