With eight grandchildren and one on the way we can't afford lavish gifts. Don't have a fixed amount and don't try to spend exactly the same on each - I agree with maxgran: it's the fact tnat the gift is something appropiate to the particular child and has been thought about that counts more than the cost. As a general rule I have an upper limit of £25 for birthdays and £15 for Christmas (more for birthdays because they are the child's 'special day' and also because they are spread throughout the year so it's easier to budget!). Last Christmas we adults did Secret Santa among ourselves instead of all buying for everyone - worked brilliantly!
I've got another 'keen'... Ouch!