Let's talk about money

Money is something I did not have as a kid, but I guess I didn't realize it because no one else had any either. There were families with more kids who got less and families with fewer kids who got more, but the families basically all evened out.

Until we moved to a better school district...and the kids had Guess? jeans and Benneton sweatshirts and straight hair with no bangs instead of the big hair with big bangs we had where I was from. And then, the kids had cars. Their cars were nicer than the teachers' cars. My sister drove a 1973 Chevy Impala in 1989. It got from A to B and could carry her 25 closest friends. She would have been laughed out of the parking lot at my high school. Few kids had after-school jobs and most spent money for prom and things. I spent money too, but it was money I earned by working 20 hours/week. When AP exams were offer at $72 apiece, I wondered how I could possibly afford them (I needed like 7 my senior year).

When I got out of (very well-granted) college with some debt, I freaked out. I did not want to be my mom. She's a good lady but not the best with money and numbers. So, I quickly paid off my student loans and saved up a down payment for a house (which I bought right before my 23rd birthday). My husband and I both make nice salaries. I mean, we're not pharmacists, but we do just fine. We live in a nice community with reasonably priced homes and good schools. We save. But, really, we don't have to worry. Even when I wasn't working, we had plenty, though certainly not what we have now. When I said things got tight, I should have added that there was no money left at the end of the month after paying all our bills and fully contributing to our savings.
So, even if something bad happens, we'll be OK with money. But, what do we teach our son? I already know the rule for in the store. If I say, "no" and he continues to pester, I will just add, "We don't argue over money." But, this strategy can only last so long. Some day, he'll be 12, and I will need to teach him about money and responsibility and I want to instill in him a little fear of not having enough some day, just so he knows and feels how important saving is. He will never know not having a need fulfilled. I will never ask to borrow $20 until pay day. He will never know any sort of real deprivation. How do I make him frugal?