Around here Asda dramatically reduces the price of food that are almost out of date. They typically do this at 8pm and a lot of stuff is 20p because they want to clear it. You can get bread, cookies, scones, sandiwches, fish. It depends on what they haven't sold. The downside is that you have to eat them quickly. Also shop at supermarkets like Aldi or Lidl instead of Tesco/Asda/Waitrose because they'll have cheaper stuff. And don't buy big brands if you can help it. Food quality may be bleh but it is very cheaper.