If you have a smartphone, I recommend the Olio app. It's designed to reduce food waste, but if you can pick up useful food then it also saves money!
You can give away food you won't eat, but also there are volunteers called Food Waste Heros who pick up unsold food from various supermarkets and distribute it through the app. There are a lot of salad items appearing now, often a lot of bread but not so much recently. Use By dated items have to be given to you by midnight (or frozen if they say they can be and the FWH has freezer space) so you'll need to be able to collect in the evening for those, but best before can usually be collected the next day. I've started doing some FWH collections, and a high proportion of my veg intake is now free! I've also sometimes picked up some minced beef or other meat too.
Salad and stir fries often end up still leftover, so if you want those you will make the FWH very happy too! Iceland collections tend to go up around 6.30pm and Tesco/One Stop around 9-10pm on the app, and you can set what distance from home you want to see what's available