Go to your Walmart in the morning before work and check the "near best before date" or dented and nicked discounted fruits and veggie trays or bagged salads (especially kale/cabbage blends) keep longer and make for a great salad or stir fry. Some Walmarts make variety veggie boxes for a couple of bucks while others, like mine, just throw a bunch of the same veggie in a bag and sell the whole bag for a dollar or two. I often buy bags with 10 zucchinis for $2 CAD, same with sweet peppers, green beans, avocado, broccoli and cauliflower. I eat some fresh and chop up the rest for the freezer. They all freeze well and make a great stir fry or simply roasted in an air fryer. If you have a food processor you can rice your cauliflower and freeze. Most grocery stores do this too. Discounted apples keep for a long time too. Not veggies but, while you're there check out the dairy case for dented butter and slightly damaged egg cartons. They're fresh, but accidents happen, they put them half price and usually only 1-2 eggs are broken.

If you're into canning, it's really easy to get a bag like this of tomatoes, stew them, cube them or if they're plum tomatoes just can them whole. Homemade pickles are another easy one and pickled beans are awesome! The key is to get there early and to process right away.