Money Tree? Is that appropriate?

by Granny M.
(Texas)

My 18 year old grandson is graduating from high school on June 5th. I'm having a celebration party afterwards for him and I was wondering if it would be totally classless if I asked those attending not to spend money on another movie poster, gift card or CD, but to give money for the money tree that will be used for a down payment on a used car for him.

My daughter has raised him alone as his dad has been battleing a drug addiction out of state for many years. She works very hard and is having a hard time making ends meet. My grandson wants to go to a local community college this fall, but without a car we don't see how he can.
Thank you.