The way I worked it was, the kids had things that they were responsible for daily, just like everyone in the house. They did not get paid for those chores, like taking out the trash or keeping their room clean. Chores beyond that were paid. Like washing the car, cutting the grass or what ever else needed to be done that they were willing to pimp them selves out for. That's just how I did it...... ;o)
That's really up to the parents. I don't think that kids should be paid for every chore they do, but maybe give them a little money when they are doing extra chores. For example, I usually got paid if I babysat my siblings for more than an hour. And if one of us wouldn't clean our room, my mom would pay another sibling to clean it. That didn't happen often, because none of us wanted a sibling poking through our things.
I never got paid for Chores and keeping up with the house it was just expected and when I did get paid I really worked for it. Also if I really needed money they gave it to me or bought me want i needed, but with that being said I also don't ask all the time and only ask if I absolutely need it.