I can only tell you what works for me.
Cleaning products, all smartprice or own brand Waitrose or sainsburys because I hate the idea of animal testing. All purpose cleaner watered down 50:50 water in a spray, dishwasher powder not tabs, white vinegar from Aldi for limescale & as fabric softener, soda crystals for dw maintanance wash, make my own laundry gloop to wash clothes in, plain caustic soda for cleaning sink traps.
Meat, fish, dairy all Waitrose online. They do good meat offers & a loyalty card that gives you 20% off a selection of items. They honour the 20% if the item goes on promo too. I do a three week meal plan & freeze everything in portions. They send me regular £10 off a £100 spend.
Frozen/Grocery stuff, don't buy much but what I do buy is Aldi/lidl. Their Mayo is nicer than Waitrose & the breads better too. I make my own stoneground whole meal loaf for me. Dh is a white sliced man.
Lunches. Sandwiches for Dh & a vegan soup based on lentils or pulses for me. I use Jack monroes recipes a lot. Its all store cupboard stuff so I always have lunch in. I could live on her spicy lentil soup.
Cakes are made using vegan recipes, very cheap to do & again all store cupboard ingredients. Homemade rice pudding on the hob, quick & filling. Much easier than using an oven. Suet puddings are divine, cheap & cook in a slowcooker.
Tea. Tesco smartprice. I buy a 1000 bags at a time as Dh drinks tea more than coffee. A relative commented on my lovely tea once & asked what it was. When I said Tesco smartprice the cup was put down.
Coffee. Aldi whole bean. I've tried everything from illy to Waitrose own brand & always return to Aldi.
Potatoes. 54lb bag from farm shop is £6 & lasts 4 months. It's my staple carb. You can get huge sacks of rice online, or pasta in the supermarket. Same for polenta, cous cous etc. We used to buy microwave rice, now I buy Tilda in home bargains for £1.
I have monitoring apps on my phone & iPad, they pay out in Amazon vouchers which I use for the cats food. My last three weeks supply of gourmet was £4 using vouchers. I do online surveys at night with valued opinions & use that for Amazon vouchers too. I have mobile xpressions & Ipsos media cell on my phone.
A weekly meal plan is;
Eggs & toast for breakfast for me, Dh skips.
Soup/sandwiches lunch.
Dinner;
Pork joint, roast potatoes in beef dripping, marrowfat peas cooked from dry in the slow cooker, home made Yorkshire pudding. Gravy.
Chicken curry, egg fried rice & naan.
COD & chips. Home made mushy peas.
Doner Kebab, salad & chips.
Cottage pie & veg. I sprinkle gravy powder over fried beef mince to make the sauce.
Sausage dinner. Mash & veg with frozen home made Yorkies.
Beef joint, all trimmings.
Burger, chips, beans or salad.
Whole roast chicken, all trimmings.
I've found home made breadcrumb stuffing, yorkshires made with 50:50 milk to water & sr flour, roast potatoes made with lard or dripping, marrowfat peas cooked from dried not tinned all so much more filling than what you can buy pre-prepared. I do big meals so there's no snacking.
Anyway that's what I do. This weeks food for us is £30 & d cat is about £1.30.