When my kids were little, we let them know that Santa’s stuff isn’t free. If your parents have jobs, then Santa expects them to pay; it helps Santa have some things to give the kids whose parents don’t have jobs. And we had a limit per child of what we could give Santa.
It helped hem get the concept. I remember explaining to my eldest–with the ADHD–that if he got everything on his list, the other 2 wouldn’t get anything, so how fair was that? He figured it out, and pared down the list. he was 7.
As for allowance, we tried a dollar a week for each year of age, when we could afford it, but it really didn’t work; I’m sure we didn’t do something right!
Birthday and Christmas money was easy: they had savings accounts at the credit union. Half of any gift money went into savings, and the rest was theirs. the idea was that when they were 16, they would have a good start for buying their first car. It was a worthy goal, and one that they could see as a good thing in the future. we did allow them to take money out for spending money the year we went to Disney World, and we matched that amount. And one of my sons wanted a drum kit, which we let him buy with his car money; later he didn’t have enough money for the car he wanted, and had to buy something that cost a little less. Certain items, we paid half and they paid half.