I figured I'd share my experience as well - this is coming from the point of view of when I was a kid, not as a parent
When I was fairly young (probably six or seven) my dad gave me a "job" at his grocery store. I was paid $1.00 per hour, and at the time it seemed like a lot. Granted, being so young I couldn't do a whole lot, and it pretty much boiled down to stocking and facing the bottom two shelves in the store (which the "real" employees didn't really mind, as they had to crouch constantly to reach them and they were just my height)
I was never forced to work, but my father encouraged me to do so. Obviously, I didn't work excessively, but I do believe that it taught me to work hard for money - I quickly realized that money didn't just grow on trees.
When I was in fifth grade or so, my father started giving me a weekly allowance - with a catch. My allowance was $40.00 per week, but I had to take care of cleaning the house and the yardwork. Forty bucks a week may seem like a lot, but the reality of the situation was at that point forward I was responsible for my own expenses. Although my father wouldn't let me starve, of course, I paid for my own "hot lunch" meals, my field trip fees for school, even my own clothes, and of course anything else I wanted. This included going to movies, renting video games, ect.
This was by far one of the best things that he could have done (at least in my opinion) to help me understand the value of sacrifice and of saving. He encouraged me to save at least half of my allowance - which I did. However, I learned at a young age that necessities always come first (I learned that my first week of allowance when I couldn't afford "hot lunch" after blowing all of my money the day I got it on toys) and if you have a goal, sometimes sacrifice is necessary (I spent as little as I could for quite some time to save up for a Super Nintendo) I also learned to save up for known expenditures I would have in the future (back to school supplies, Christmas, ect)
Looking back on it, I'm very glad he did what he did. I'm pretty good with money nowdays, and can pretty much say with certainty that he is the sole cause for me learning so young.