We meal plan and have done for a long time. For us it wasn't about budget but about cutting waste and being organised. It naturally helps with budget too though, as we know how much we are spending and because we are geeks who track it all on a spreadsheet how much we will spend depending on what we cook. The majority of our meals rotate, meaning we have a well stocked larder which gets good use. We then have one meal a week which is something more fun that we have to buy more for. We shop around, using great local shops for spices/lentils etc.
We are a family of four but the littlest is breastfeeding still. So this is for two adults and a five year old.
A typical week's dinners goes something like:
Homemade chicken curry, daal, rice, chapati with supermarkets bhajis and condiments
Roast chicken with roast veg
Chicken Fajitas with rice and cheese
Grilled chicken with sweet potato fries
Spag bol with garlic bread
Burgers and wedges
Babi ketjap and rice (Indonesian pork curry)
DH used the left over roast chicken/curry/risotto etc for lunches and dinners at work.
DH eats cooked chicken or paneer for lunches at home, I have the same or eggs or tuna (heavy on the protein, basically!). DD has sandwiches with fruit and/or veg. Breakfasts are high protein yoghurt, toast, cereal, croissants etc.
We spend between £40 to £60 per week on our main shop, depending on how meat heavy we are. That doesn't include nappies or other baby related stuff. We will do a top up shop sometimes to raid yellow sticker meat etc.
We changed to online shopping when DD2 was born in October. It does make a difference to how much we spend and we are definitely wasting even less.