I don't get it, i mean out if the whole supermarket i only buy a stock average of 60/70 items, so i don't buy most things
The point is, like @Ginfordinner says, is to let everyone know how worthy and morally superior you are because you never buy anything processed, frozen, canned etc and wouldn't know an Iceland if it was built at the end of your road.
The only things we never buy are those at full price when they're the type of product that's always on offer somewhere, eg canned tomatoes, cleaning products, toiletries, tea and coffee, petfood etc. Everything is either on offer or from Aldi or Lidl where they don't really do offers, but most things are cheap anyway.
On the subject of fabric conditioner, we do use a bit in each wash that doesn't contain towels, because it makes things softer and less creased, it doesn't smell because DPs sensitive skin needs the 'gentle baby' variety and a bottle lasts ages, I'd be surprised if we spent a fiver a year on it, so never going to be a noticeable saving if we did without, which we don't want to.