catsmother With regards vastly reduced items, just ask store staff when reductions happen and to what level! The ones I speak to are always happy to advise 
I am one who feeds a family of 4 (2 adults 2 toddlers) on less than £50 per week for everything including nappies, toiletries, cleaning stuff, cat food etc & I will say we eat very well!
Have just had roast lamb, hm yorkies, roast pots, cabbage & leeks (reduced to 30p), plus a pudding of treacle tart (reduced to 9p) & cream (reduced to 24p for a large pot)/custard & I worked out it came to £5.70 between us all. There is enough lamb over for DH's sandwiches tomorrow, pie tomorrow & scraps for DCat. Tues will be chicken drumsticks, jacket spud & veg, next day maybe fishcakes, mash & veg. Then haven't thought beyond that! Have well-stocked fruitbowl & snack shelf too. We get our 5 fruit & veg a day (& more) by using a mixture of fresh, frozen, dried & tinned, buying reduced & freezing. We eat meat probably 5 days out of 7, fish 1 out of 7 & the other day.
We also last week purchased a lamb (weighing 17.8kg when butchered) from a local farmer (who I met at a baby group!) for £90, which we shared with my parents. This will feed us for around 20 meals, with the added bonus that it is delicious, local & organically reared - I know, I have seen the farm it lived on (went there to fetch it)!
I buy things in bulk when I see a good offer/reduced & store it (have 2 freezers, got 1 as an Xmas pressie from ILs!)
ATM, we shop as we do out of necessity, but we have always done it this way & when we had more money to spare, the savings went towards a nicer holiday or more days/nights out. Plus, I kind of get some kind of thrill (sad, I know!) at eating delicious food for next to nothing.