To help keep costs low, Mercedes uses a Blue Light Card Shopping Card, layering the savings on top of existing supermarket promotions for a double discount. Once you have purchased your Shopping Card it is delivered digitally straight to your Blue Light Card app, ready to use. But adding the Blue Light Card layer is the best part of the hack, shaving off an extra £3.23 on the spot. Joe Mathison, head of strategic partnerships at Blue Light Card, said: “We know how stressful and expensive food shopping can be for parents over the summer break. Visit the Blue Light Card site to find out more about the available discounts and who can redeem.