My daughter wants a Nintendo DS for her birthday, and I am considering something like $6 for the 6 year old...?

I do not want to be completely rude, though. Is there any way to ask for $6 in lieu of gifts? I know that when I buy birthday gifts that I generally spend much more than $6 - I am hoping to make giving a gift to my daughter 1. easy and 2. affordable. BTW, we are having a backyard BBQ and inviting her classmates, family and friends... and we are also inviting the parents to come along to the BBQ. Believe it or not I got this idea from my psychiatrist who mentioned that he did something similar for his son when he turned 10 and the guest were relieved to not be stressed about the gift and the money was, again, less than they normally spend on a child's gift. So... thoughts, comments, suggestions were all be very much appreciated.