If you're about to tuck into a Big Mac and a 20 box of nuggets, your McDonald's receipt is probably the last thing on your mind.

However, throwing your receipts away might cost you some serious pennies in the longrun, as one savvy saver has proven.

Writing on the popular Extreme Couponing and Bargains Facebook page, one savvy money saver explained how each McDonald's receipt contains a unique survey code, which can be used to get a Big Mac and fries for £1.99 - saving you £2.29.

She wrote: "MCDONALDS HACK. Don’t throw your receipt and use it for the discount. I always keep Mcd receipts in my wallet for use it in the future.

"Doing the survey doesnt take more than 2 mins."

She explained: "£1.99 for Big Mac + medium Fries (yes you have option to change the burger). Sometimes i change it to Quarter Pounder. Big Mac + Fries without receipt= £3.09 + 1.19 = £4.28. With receipt = £1.99 You save £2.29

"If you and your partner use same hack (yes you need 2 receipts on separate orders) you can save £2.29 x 2 = £4.58. Enjoy!!"

She advised that you can swap the Big Mac for another burger if it's not what you fancy - though this is at the discretion of the restaurant manager.

"Yes, you have option to change the burger. Sometimes I change it to a Quarter Pounder," she said.

So next time you're at Maccies, KEEP YOUR RECEIPTS! And get saving those pennies for Christmas.