It's essential and part of being a parent to "teach" your children about money. Whether they listen and take it on board is a different matter entirely. My parents talked to me about money from an early age and we did the same with our son.
Not in a negative "we can't afford it" kind of way, but with logic, i.e. "would you prefer to spend your pocket money on something like sweets or comics where you have nothing to show for it or would you prefer to save it and buy something you'll value that will last for a long time?" I used to save my pocket money to buy model railways, and my son (even when young) saved significant amounts from pocket money, birthdays & christmas to buy things like wii/xbox games, an iPad, replica football kit, etc.
Now he's 20 and he's got a very responsible attitude to money, now he's at Uni. He got a decent amount of money (from an inheritance in trust) at aged 18, and we're proud that he's not wasted any of it - it's mostly still sat in the bank. There's nothing he'd like more than to buy a car with it (he'd fed up of driving our old banger we gave him), but he also knows he's going to need money for relocating for his first job after Uni (almost inevitably he'll be moving to London/SE which is where the jobs are), so will need money for a rental flat deposit, probably a car, and ultimately a deposit to buy a flat/house. So his ambition is to keep at least 75% of his inheritance, the other 25% being drip-fed over 3 years for living costs etc whilst at Uni to avoid taking out full student loan debts.
But even with that kind of mature attitude, he can still "waste" money on small things and, to give him his due, he knows when he makes mistakes and tries not to repeat. For example, at first, he'd go to the campus convenience store and buy 4 ready meals, that were actually 3 for a fiver. He couldn't explain why he bought 4 rather than just 3 to get the offer and then buy another 3 a day or two earlier next time. But he's never done that since! Another "cost cutting" thing he now does is do everything in town on the same day, so he can just buy a "dayrider" bus ticket and do his main supermarket shop on the same day he goes to watch a football match and have his McDonald's tea on the way back - at first, he'd do all that on three different days thus buying three separate dayrider bus tickets.
Having said all that, he's not averse to paying through the nose for things that matter to him, i.e. he'll think nothing of paying close to £100 for replica football shirt, but for him, that's important and he values them (he's literally got half a wardrobe full of them, all in pristine condition, going back years!).
What I can't explain is why me and my brother are so different. We both had the same parents, both had the same upbringing, but whilst I'm highly debt averse, he's tens of thousands in debt and has been all his life, and has little to show for it - he got every credit card/store card going from a very young age (back when easy credit first became commonplace in the 80s), never pays anymore than the minimum balance and pays, literally, hundreds of pounds of interest every month. All gone on disposable clothing, gadgets he uses no more than a handful of times. I don't know how he sleeps at night, but he just doesn't seem to care.