I only buy toilet paper, kitchen towels, nappies, wet wipes, shower gel, shampoo, dishwasher tabs, laundry detergent when it is on offer and bulk buy. Ditto wine, cheese, yoghurt. I always look at what offers the best value per unit/100g etc.
Shop in Aldi for specifics that are equal in taste but cheaper, eg bread, milk, butter, chocolate, biscuits, brioche, French cheese, Greek style yoghurt, smoked salmon, pasta sauce, basic medicine.... Savers sell Tempo tissues which offer fantastic quality at bargain prices.
We buy the majority of fruit & veg from market stalls. Much cheaper, more seasonal. Though it can be hit & miss quality-wise. I don't online shop much as I like to see the offers and then fit meals around them. If I want to save money I send hubby to shop, he doesn't get tempted and only buys what is on the list!!! I also avoid shops like the plague and mostly buy if on sale.
We spend quite a bit on food but we always cook everything from scratch (and rarely eat out or use take away, though I would love too!). I make my own pizza using the bread maker for dough. Healthier and cheaper. I often let the children make their own individual pizza, shaping their dough, spooning the topping (I precook the veg in passage so it is nice and soft and I can hide loads of veg in) and then topping with grated cheese. It is a hit at play dates and takes care of all most allergies/ intolerances/ exclusion diets as I can tailor it to the child.
I like baking and I make all our cakes, including birthday cakes. Often invite friends for tea and cake rather than a meal, which is easier for everyone when young children are involved as they don't need to sit down for long and no babysitters are required. Much more casual and dirt cheap. All birthday parties are at home, I home cook all the food that I know kids will eat (no limp sandwiches), I make cocktail sausages, pizza, salami, baguette and butter, finger veg and fruit, chocolate, cake and jelly. It all gets eaten up, very little gets thrown away and even parents enjoy tucking in.
I try to make meat last 2 meals. Eg roast chicken day one, chicken in cream day 2. If not quite enough (eg curry) I bulk it up with a starter or a pudding like pancakes. Soup Saturday lunch and jacket potatoes Sunday lunch. We are trying to go veggie more often and cook more with pulses though haven't quite cracked it yet.
The majority of the kids clothes and toys, especially under 5s have been bought second hand. IKEA is great for kids craft and their wrapping paper is the best quality ever. I don't use clothes conditioner. I use the library for books, though to be honest I don't have much time to read, the Saturday paper lasts all week!
Still not enough though... :(