I've been making my own bread and biscuits rather than buy them in plastic bags. (For biscuits at least this doesn't save money due to the price of butter, but oh well.)

I've also taken to buying milk powder and making up milk as I need it rather than again plastic containers; someone pointed out coal is used to dehydrate the milk, but otoh I'm using less milk than I would otherwise so idk what the net effect is. It does at least mean I no longer discover the milk has turned to yoghurt in the container, and procrastinate cleaning it so much I can't clean it enough to put in the recycling.

Spring onions grow happily in a pot indoors, from the roots of the spring onions bought from your regular source.

Buying a deep freeze has been fantastic: I can now buy in bulk, or cook in bulk and save portions, or freeze fruit when it's in season (the lazy version of bottling :-)).

I've been experimenting with waxed food wrap instead of plastic. Unfortunately it clashes with my tendency to forget food in the fridge until it's gone mouldy, because the wax can only be washed with cold water and soap, which I'm not certain is sufficient for mould....