I don't have many tips but they might help?
Cleaning products - have a look at home bargains or Wilko or online pound store and do some price comparisons. It works out cheaper for me to go to Wilko and do a big cleaning shop (I say big, it's not really!) and get everything in one go
If you eat something, it's not perishable and it's on offer, buy it. Even if you don't need it that week. Coffee for instance say is £5, but you see it at £3, get it then you never have to pay the full price for it. Find some storage room for this. Works with anything like beans, loo rolls, pasta, peanut butter, washing up liquid.... anything! Always aim to buy it at the lowest price
It means sometimes I have 3 tins of coffee, sometimes 1 but I'm never paying full RRP for it
Again home bargains etc can have snacks cheaply, I found multipacks (5 to a bag) of crisps were 50p so I checked the date and stocked up. Same packs were £2 in the supermarket
Cleaning products again but hot soapy water goes a long way, if you use sprays then watch how much you use and always give the product time to work. Washing powder usually works out cheaper and is better for machines
Check Amazon for deals on not perishable stuff - I eat marmite rice cakes all the time, they were on offer, so I bought them! Also worth checking loo rolls prices and stuff like that on there too as sometimes subscribe and save is cheaper
Stick to cheaper fruits and veg. Stuff like apples, bananas, carrots, cabbage... bulk meals out with them too. I'm not advocating the MN chicken style
but stuff like carrot and potato mash is filling, using stronger cheese for more flavour with less, chucking some extra veg in meals
Try dropping down a brand, or a new product if it's on offer. Look for reduced food too