allowance is a great way to start the money learning proccess. But you shouldn't pay them for cleaning their own rooms. that should just be the base of allowance... you get paid for wat you've done as long as I haven't had to tell you to clean your room this week (If a clean room is important to you) They should only be paid for doing work that involves the whole family, dishes after dinner, yard work, bathroom cleaning, vaccuming, but not just once a week, they have to do their chores all week to get paid. They should have a check off sheet for everyday, maybe one of those calenders that stick to the fridge or something. Bad behavior in school or at home, should also effect the allowances. Squabble happens but fighting or name calling should not. Money is important to kids for some reason, they enjoy having some of their own, it makes them feel like a big kid, and a little independent and the Creator knows how often those fights about treating them like a baby happens! My lil brother has had allowance since he was 5 years old. My mom would give him five dollars a week to clean and vaccum the living room. Even if it took him three months, he would save up for that video game he wanted. But thats the thing, since he got allowance, he wasn't allowed to walk up and ask for a video game, he usually had to come up with at least half. Nowa days, since he is now 15 he must come up with 3/4 of it. So, maybe if you made it clear to your children that if they want allowance then that intitles them also paying for the things they don't need like video games and dvds, they may not be so stoked on the idea any longer. And if they plan on going to the grocery store with you, make it very clear they'd better bring their own money if they plan on trying to get anything out of the trip.
P.S. I wouldn't go for the idea of having them pay for the things they do need, like a pair of new shoes... if they just want them and don't need another pair, then yes. If you have them paying for their school supplies and new school clothes, you will only end up with alot of resentment. That is money you will have to spend normally no matter wat, don't take it from them, they will feel like you are taking advantage of the fact that they work hard for the money you give them and it isn't fair that you take it back for things you would have to pay for anyways. Believe me, I have witnessed this time after time again.