My six year old get $6/week. One is a Disney dollar she has to save for next year. One is $1 she has to save. The other $4 she may spend as she chooses.
My four year old gets $4/week. Her deal is the same as above - One Disney dollar to save, $1 to save and two to spend.
I plan to give them each a $1 raise on their birthdays so their allowances will equal their ages but they will be required to save at least two dollars a week. They each have a few chores associated with their allowances (although my four year old doesn't really get the concept quite yet). We have only been doing this for three weeks, so we shall see how it goes...