I find it easier to control the amount I spend if I do it online - you can see what you're spending as you go along, and weigh up the various options of quality (or brand) vs price. You may save time and effort by buying ready peeled/chopped/prepped foods, but you're paying for the luxury, too - may as well get a decent food processor and get it to do the chopping etc. for you. Cooking from scratch is easy if you can read - there are recipes for literally everything online, and definitions of cookery terms - and videos to follow, too if you're lacking in technique.
If you don't learn to cook, you won't be able to teach your children how to cook either, so they'll 'inherit' your problems in the kitchen. You don't have to cook from scratch every night - once or twice a week would be enough to start with, and to see a difference in your grocery bill.
The meals I produce are far nicer than anything ready-made, no matter how 'luxury' it is! I'm a food lover, but I'd struggle to spend that much on food every week, even if I tried! We eat things like duck eggs, speciality cheeses, high quality free range meat and seasonal vegetables, loads of grapes, good coffee and tea and so on - not budget food (I know, we're lucky, and I appreciate that), and most weeks the bill (including household stuff like loo roll and washing up liquid) comes to around £100 for 2 of us, plus two dogs and a cat. I'm sure you could cut down your food bill without sacrificing quality, if you were willing to try a bit of cooking!