Buy fruit at the end of the market day and you will find the prices drastically reduced as the traders do not want to take it home. Buy the supermarkets own brands of pasta, bread, pulses, soups, which are usually much cheaper than those by known brands. Roadside sales of fruit and produce can be cheaper. Find a dairy farm and buy your milk direct. Mostly...look around for who/what/where provides the cheapest foods. Get a book which describes the rations that people ate during the Second World War....they ate very healthily but ate what we would think of as little!.......Fortunately I don't have to these days but you can live very cheaply and healthily if you wish. With the extra weight I am carrying it might be a good idea for me to follow my own advice...MMMMMMMM.
Best wishes, Mike.