Australian retailer Coles Myer is thought to be in the final stages of negotiating a deal with US oil giant Shell that would give shoppers at Coles' stores the opportunity to gain discounts on petrol from Shell service stations. Shoppers who spend a certain amount at Coles or Bi-Lo stores will be rewarded with a voucher that entitles them to a few cents off the price per litre of petrol at Shell stations.