It’s not just about buying in it’s about making best use of what you already have too.
So learn some new ways of cooking, new recipes, think outside the box eg carbs are pretty much interchangeable flavour wise, plain noodles, cous cous, rice etc will also work fine with a “pasta” sauce.
If you’re short on cooking oil have you plenty butter in? Or even water (works just as well for stir fry type dishes)?
Don’t feel recipes have to be followed to the letter, if you’re missing a herb or other minor ingredient you can substitute or just omit usually.
I can’t eat normal onions so got shallots in and been using those where onions are mentioned.
Yesterday I made a ratatouille but I’ve only white vinegar and normal granulated sugar in rather than the red wine vinegar and brown sugar most recipes recommend - it worked just fine.
Be flexible.
@ladybookreader is right on beans, I’ve ordered butter beans (annoyed at myself for not getting sooner) as I’ve used these before to make my own baked beans using Passata, purée, sugar and vinegar. Been a while I may need to look up a recipe but as they’re “unflavoured” I can also use them in stews (could maybe add to the ratatouille which I’ve now 4 portions left of), chilli, cassoulet type dishes...
“do you all have massive freezers or are you creative with storage?” I have a crazy tiny kitchen, sod all counter space or storage and only a 2 drawer freezer.
Currently in my freezer is:
A HUGE bag of oven chips (mistaken purchase no idea it was that big but it’ll get used eventually)
A loaf of bread (slices come away easy as and it toasts just fine)
Crumpets
2 portions of ratatouille
1 portion of “chicken” (quorn chicken I’m veggie) casserole from a batch I made
A cheese & tomato pizza which came in plastic wrap AND cardboard but I discarded the cardboard part to give me more space
2 portions of grapes frozen (delicious frozen)
A packet of fresh filled pasta
A packet of grated cheddar cheese
Sausages, Kiev’s and crisp bakes for lazier days (although I’ll probably use sausages for casserole too and that way I’ll get an extra meal out of them)
Repackage things if it gives you more space, often the original packaging is over generous
At this point it is more sensible and kind to not panic buy but certainly planning so you minimise waste helps a lot.
See this thread and similar ones for ideas
https://www.mumsnet.com/Talk/_chat/3857078-Food-thread-Favourite-leftover-dishes-avoiding-waste-menu-ideas