DD has saved over the years from birthdays and christmases and also from grandparent money when she goes and sees them. She enjoys THREE just 3 computer games and she now wants a gaming computer. The one she wants is 2 grand 
she has about £1500 in the bank and as her birthday is 2 weeks before Christmas she will get around £500 for them both combined (in total from everyone). So she wants it then.
I have so far said absolutely not, it's far far too much and it's better to save it for maybe a car when she's old enough to learn to drive. AIBU