General Tip: frozen vegetables
Ready diced frozen vegetables are a no chop, quick, cheap and widely available way to get vegetables in your diet. Since they are frozen, you also don’t have to worry about them spoiling if you don’t get through the bag quickly.
Adding a handful or two to things like pasta sauces, soups and curries works well. They also make a great healthy side to pretty much every lunch/dinner if you boil them with a stock cube (vegetable or meat flavour, both work fine) to make them taste a bit nicer.
Supermarkets generally have a few different varieties so you can pick what kind of vegetables you want to go for too.
For UK people, Tesco has a 1.3kg bag for 89p (68p/kg), Sainsbury’s Basics is 1kg for 80p, Morrisons is 1kg for £1 and ASDA is 1kg for 77p. (From supermarket websites)