Tesco's price cuts have helped reduce the average cost of groceries by 0.3% in the past month. The Grocer Price Index, based on 100 products, shows the average price of a trolley across the big four was £180.14 last month compared with £180.62 in September. Tesco's trolley fell 3.5% to £174.42, while Morrisons' rose 1.19% to £183.42.