Kantar Worldpanel, which compiles price and sales data from the major chains, noted a 14th consecutive slowing in the annual pace of price rises at the tills in its latest report on the sector.
It found that savvy shoppers took advantage of the intense competition for business among rival supermarkets by saving £1.3bn through purchases on discounted items over the four weeks to 14 April.
That amounted to a saving of £46 per household, Kantar said.
The rate of grocery inflation fell from 4.5% to 3.2% as a result, the data showed.