Two possible ideas:
1 - A giant Christmas card. It won't require much money: construction paper, markers, glitter & glue, etc.
2 - Make an ornament for your Christmas tree. Dress it up, make it really special. Maybe make one for each member of your family. :)
“I am assuming you’re thirteen years old...
1 - A giant Christmas card. It won’t require much money: construction paper, markers, glitter & glue, etc.”
And if he’s an adult, he should have it notarized.