Hi OP,
I'm in a similar situation, belt tightened due to lack of cash until May next year. Only 2 adults and 2 cats and I'm on a budget of about £100-£130 a month for everything.
Sorry for such a long post but want to try and help if I can.
I only shop at Tesco so anything I say only refers to there I'm afraid. Other shops may be cheaper!
Mr BC must have meat otherwise he sulks.
You need to channel your inner cook, price checking and list guru! :) If you shop online check and remove things constantly from your basket until you are happy!
Now is NOT the time to worry about where your meat came from as you can't afford free range/ organic (unless it's on special offer) but anyone here who pulls you up on this can sod off IMO.
Cat food is a MAIN problem as my 2 will only eat certain brands and will turn their noses up at "shop own". However, I did find in the past that they loved Lldl and Aldi own brand cat food so if yours are fussy buggers try them on theirs to see if they like it as it may save you some cash.
Fresh veg - get it cheap and freeze if possible if you don't use right away or starts to look a bit sad. (like cheap carrots and greens, clean and slice and freeze in portions to then put in recipes or boil just to eat) I also get the biggest box of mushrooms and have been known to get 2 if they are on special, thinly slice them and dry them in the oven on low and then store in a tight jar for adding to things!
Get a HUGE brown bag of spuds!! Also a 5kg bag of onions! Will last and so many meals you can do! So much cheaper in the long run.
Fresh fruit - In an ideal world yes get it but if you can't afford it don't. I only get cheap bananas and small apples once and then don't get anymore if they are gone until the next month.
Chilled meat - DON'T spend your money on cut up stuff. We use a lot of chicken
if you use turkey buy cheap turkey legs/ thighs and take meat off it to use.
Tesco also do chicken legs/ thighs fresh for £1.25 for 750g. I use these ALL the time in cooking. (if you don't like the skin, take them off and fry these dry and use the fat from the skins to cook other stuff in!)
Cheap chicken wings (they do cheap fresh or big bag of frozen) are great to nibble on with huge pile of home made potato wedges when you have the teens round!
Their mince is £1.49 for 500g - very nice and I save the fat for cooking! (do not buy frozen mince as costs more (for some reason!))
They do cheap large whole chickens as well for under £3. (good for teens to rip apart for sarnies etc)
Also if you like bacon get their cooking bacon (about 75p for 500g I think), can be added to pasta dishes (I do a chicken and bacon pasta bake with a whizzed up tin of tinned toms, with some grated cheese in it and spices with a topping of grated breadcrumbs more cheese) and and pies etc!!
Pork - If you use pork get a cheap cut and cut it up. (we rarely get it as can be pricey unless its cheap chops)
Frozen stuff-
Frozen legs/ thighs of chicken (about £3 for 2kg) use in stews, defrost and roast or use meat in pies etc etc! Don't bother with breast meat as too pricey.
Frozen sausages - tesco do 20 normal sized for 90p. They aren't the best but good for filling up tums and make a decent sausage casserole and also can be used cold in sarnies when the thought of more cheese makes you want to weep.
Frozen peas/ veg/ fruit - get the cheapest, again can flesh out meals. frozen cheap fruit nice in porridge and as a pud. (we only get it every now and then)
Other fridge stuff:
Yogurt - if you like it and NEED it tesco do HUGE tubs of natural yogurt for about £1 - £1.50. Flavour with jam or frozen fruit if need be
Cheese - tesco do seriously cheap mature cheddar, huge block of it. Also get some strong mustard and sandwich pickle, salad cream etc for sarnies, helps with cheese sarnie overload.
Sliced meat - get the wafer thin cheap own brand - I got 400g for about £1.50, really nice in sarnies. So far one pack has lasted 7 days for sarnies for MrBC (plus a few slices for the cats cos they look at me sadly)
Butter/ spreads - one thing I get is 2 packs of butter (nicer on toast) but use cheap spread for sarnies/ cooking etc. (make sure you can use the spread for cooking if you want it for that)
For store cupboards:
EGGS! - 15 for about £1.50 - So useful! Omelettes (I bung mine under a heated grill in the pan and they puff up and go HUGE!), eggy bread, eggs for sarnies, cooking, snacks etc etc! (MrBC loves a fried egg and cheese sarnie at the weekend, cheap breakie option!)
breakfast cereal - Own brands and porridge! Cornflakes seem to be the cheapest.
Own brand cheap cup a soups, fills a hole and might help as it gets colder with a couple of slices of cheap bread (35p from Tesco) . Ditto own brand cheap soups (add a tiny bit of sugar to cheap tomato soup, helps with the flavour)
Plus make your own soups. Cheap stock cubes and bung anything in!
Sauces - red and brown own sauces and all the other cheap ones taste the same and you get used to them!
Powdered milk - I got Nido (was £3) for emergency milk and cheaper stuff to add straight into tea/ coffee. Nido is more pricey than others but it's whole milk and is a god send when we run out of milk as can be used to make up a pint or two of fresh and actually tastes like fresh milk when we run out of cash!
Cheap baked beans/ kidney beans etc - can be added to bulk out stuff and baked beans can go with most meals! I have dried kidney beans as well but keep forgetting to soak them
Also cheap tinned EVERYTHING! tinned tomatoes can be used to make loads of things from spag bol, curries to salsa. l drain a tin to make salsa then use it with cheap jarred jalapeno slices to go over 49p tortilla chips with melted cheese to make nachos, might fill up the teens as a treat!) , tinned sweetcorn is normally very nice on it's own or in things. get what you know they will eat plus you can get decent tinned fruit (in juice) on special sometimes!
PASTA PASTA PASTA RICE RICE RICE - Cheap as ruddy chips and they won't go off, can be added to soups/ stews ets as well.
If you can get bulk rice get it but check prices per kg to make sure it is a saving.
Coffee/ tea - Cheapest own brands, your taste buds will adjust :)
Get plain and self raising flour (45p each for 1.5kg from tesco)/ bicarb of soda/ lemon juice and baking powder - These will be a godsend if you run out of bread as you can make soda bread from them. I have them in the cupboard all the time! really nice with soups/ stews and own it's own with spread.
Make your own biccies/ cakes - Cheap self raising flour, eggs, spread, and sugar. Basic recipe, add in jams/ broken cheap choc chunks/ lemon juice (adds a zing if making lemon drizzle cake) etc to flavour!
Spices etc - seriously, you will need these to help, check out "world foods" as you can get cheaper products (we use jarred sliced jalapenos from "world foods" to spice things up an in place of fresh chilli peppers) - check out Indian shops if you can to get large packs for half the price of the stupid little ones in most supermarkets.
Butter/ spreads - one thing I get is 2 packs of butter a month (nicer on toast) but we use cheap spread for sarnies/ cooking etc and for when we run out. (make sure you can use the spread for cooking if you want it for that)
Treats! One they are gone, they are gone. We get Tesco own 30pack crisps (£3) (they do normal crisps and maize snacks) and they do bars of choc for about 40p. I do get MrBc more snacks than I like but he takes these to work as well. We also get a couple of packs 49p tortilla chips to make super cheap nachos or as scoops for chilli con carne.
Also get a bag of popping corn (we get it for 99p). a little makes a LOT of popcorn!!
Cheap biccies!!! If you can, get a box of broken bicces! You can get some really naice ones in there, we have had them mainly full of posh choc ones a few times (plus its fun not knowing what you get!)
Squash - Get the cheap stuff and if they don't like it you can add in lemon juice and dissolved sugar syrup to make cheap orange squash taste nicer and mix them up to make new flavours :)
For household stuff - You don't need as much as you think you do!!!
Cheap loo roll - it's just to wipe your bum and bits, no one really needs 14 layers infused with coconut oil.
29p loo rim stuff - thats all I use now, once a week or when needed and a scrub with the loo brush
Cheap multi cleaner - about 70p - £1, lasts ages. Also if you are in a bind, lemon juice and vinegar will cut through grease.
Put washing up liquid on your scrubby thing, not in the water (my bottle lasts about 2 months doing that!) and then top the washing up liquid with water as you go.
Bars of soap instead of shower gel, use a cheap body thing to help lather it up. cheap and lasts for ages.
Toothpaste - You only need a pea size for adults!!! Do not squeeze a huge amount out, its just a waste! (ours now lasts ages since we stopped doing that)
Don't scrimp on underarm stuff, use what you need to use. I find the cheaper ones don't cut it for us. (get them on special when your can)
Just use cheap and mild shampoo and conditioner, nothing fancy.
You don't need to clean your carpets and if you have hard floors u can use cheap multi cleaner to wash them . Ditto a bit of multi cleaner on a damp cloth can be used to clean up most things and just use a damp cloth to wipe down surfaces if they are dusty
Washing gel/ powder - again, get the cheapest! it all does the same thing.
Beauty things - I use sweet almond oil for cleansing, moisturizing face and body and on hair etc. I got 250ml from Amazon (was under a fiver I think) and I haven't even made a dent in it over 3 months. I massage in a few drops then remove with cloth in hot water (cut up old soft towel) then massage in a couple of drops. I also use it when I shower on my dry skin on legs arms arms.
Foundation - mix with cheap moisturizer to extend how far it goes on :)
For Christmas -
Look at cheap and cheerful cuts! Maybe a couple of turkey thighs/ legs instead of a whole turkey? Small cut of beef (around £8) and oh oh!! Tesco do cheap gammon! maybe a couple of those if you like them (we freeze them coming up to Xmas)? (last Xmas I did honey and mustard glaze on a couple of the cheap gammon's and was lush and lots left over for sarnies and to add into pies!)
Make your own mince pies if you like them! same with xmas biccies. Don't make your own xmas cake, it costs so much money for all the ingredients.
Hope this helps and sorry it is so long!!