The Co-op supermarket is following the lead set by Tesco and Sainsbury's by introducing cheaper prices for members of its loyalty programme. The retailer, which has more than 60 stores in the North East, is the latest to offer two-tier pricing, with reductions for holders of its Co-Op Membership scheme not available to those who do not join up. Its move comes just days after the UK's second-biggest supermarket, Sainsbury's refreshed its Nectar Prices scheme last week to bring it in line with Tesco 's Clubcard scheme. The Co-op is the seventh-biggest food retailer in the UK, with 6.5% of market share. However, it is claiming the new scheme could save shoppers as much as £300 per year, as the battle for supermarket loyalty card sign-ups intensifies and discounters Aldi and Lidl boost their reward schemes and gain more market share.