The My Shop is Your Shop-led initiative promotes the financial, environmental and health benefits of walking to the local shop rather than driving to a supermarket.
MSYS chairman Alan Toft said: "If the round trip to superstores was just four miles, the price of £10 and under top-up baskets would need to be 20% cheaper than local shops' for the car journey to be justified.
"We want independent retailers to point this out to shoppers before they jump into their car for top-up trips. "
Dr Alan Hallsworth is currently researching the issue of hidden costs borne by shoppers driving to stores. "The giant retailers say they offer low prices when in fact a basket of £10 or less could be much cheaper at the local shop," he said.
Walk & Shop also reminds consumers that they can avoid food wastage of an average of £420 a year by controlling their food spend and buying locally.
Find out how you can join in the day's activities at www.myshopisyourshop.co.uk.