This is what we do with dd1 and dd2 (aged 11 and 9).
They get 50p pocket money per week. For that, they are expected to keep their bedrooms tidy, make their beds and put their clean clothes away.
In addition, they can earn 10p per job round the house - flat rate, no arguing! Eg - unloading the washing machine, putting the washing out/bringing in, clearing or setting the table, tidying away the little ones' toys, washing up, vaccuuming, etc etc.
Mostly they will offer to help but sometimes I say "I need you to do this for me now".
We have a whiteboard in the kitchen with a running total on, and the amount they have earned that week gets transferred to their account. They love adding on their money and it becomes a competition to see who can earn the most
The sanction is that they lose their 50p basic if they don't do their expected bedroom jobs. Also dd2 has been threatened with not going to Brownies if she doesn't buck her ideas up (she is very messy).
Works well in our house!