Home grown food really does taste much better, and it's much fresher so better for your health too! It also helps the environment as it doesn't have to travel or be packaged. You can usually avoid having to use pesticides - I do use them from time to time indoors but never in the open soil.
If you've got a garden or patio, the easiest thing (and best value for space) is potatoes. Red skinned ones have more flavour and are better at resisting lime blisters for the alkaline soil of the Oxfordshire area. They can be grown in containers as well as in the ground. Beware though - next year they'll seed themselves!
If you've just got a windowsill, then salads and herbs are the best use of space. I use troughs rather than pots so you can sow rows - make some holes in the bottom and put them on trays. Indoors, seeds will germinate all year round - just keep re-seeding in relays.
Rocket, cut-and-come-again lettuce and spinach are the quickest and best-cropping salads; coriander, chives, parsley, mint, basil, oregano etc will all grow happily in pots but take longer to grow. They'll be protected from pests and just remember to water them regularly!
If you have a larger garden, or a suitable south-facing fence, you can grow ftuit too - it pretty much looks after itself. I've got apples, grapes and strawberries and in my old house had a pear tree too. Strawberries will grow in pots but need plenty of sunshine and will only crop in summer.
Gardening is not only good for your health and the planet, it's also been proven to improve mental health, relieving stress and improving mood. And the exercise is of benefit too. If you haven't got a garden, you could consider volunteering (in better times!) for community gardening.