My parents were reasonably self sufficient (bought in flour, sugar, pasta, rice, hay, fuel, water, and animal food for instance) for many years, especially by bartering with others for other veg/fruit, honey, game and so on.
We had goats (for milk and meat), chickens (meat and eggs), raised calves, pigs, and lambs for meat (bought at low cost at market or bartered), polytunnels for veg and fruit, and grew kale/potatos/onions etc outside. Mum made cream, yogurt, butter and soft cheese plus jams, chutneys etc. She never made good hard cheese, so this was exchanged for meat.
You do eat quite seasonally, and sometimes get sick of things in season - at peak milk production, and with the freezer full, there really was a limit to how much yogurt you could eat.
I liked it as a childhood, but its a hard life to keep up - no days off or long days out if you have stock to milk.