And just to make sure, shoppers have been able to compare their shop to advertised prices of compatible items at any of Tesco, Sainsbury's Morrisons or Waitrose stores.
A quick visit to their website, put in your receipt number, and if it turns out your shopping isn't 10% cheaper, you get a voucher for the difference to spend in the store on your next visit. Simple.
The scheme quickly became popular with bargain hunters on the internet, and even spawned the term 'Asda Wombles', which referred to people who picked up discarded receipts in the car park and made money by inputting the details on the scheme's website.
According to MoneySaving Expert.com, 'Wombles' could average Â£250 a month from retrieving discarded receipts.
The was even a 'Wombles for Cash' Facebook group formed in January 2015 which grew to almost 6,000 members – with 40 making Â£10,000 in vouchers between them in a single month
In a surprise move, Asda have announced the closure of the scheme, instead promising price reductions to "keep prices low".
In an email to users sent today, the supermarket giant claimed to have invested over Â£100m in lowering the price of 1000's of products.
They say the Price Guarantee website would continue to work as normal until 3 October, and you'll have 28 days after you check to redeem your voucher.