My son just turned 16. I didn't do a party like you, but I gave a neat present (not a car) that he liked. I wrapped 16 pennies in a tiny box, 16 nickels in a bigger box, 16 quarters, 16 one dollar bills, 16 two dollar bills, 16 five dollar bills, then the biggest box was a hoodie he wanted. When he saw the one dollar bills, he started counting and looking at the bigger boxes and he got really excited. I was afraid he might be disappointed when he saw the hoodie, but he wasn't. He said he knew I'd never give him 16 twenty dollar bills (he didn't think of two dollar bills, so he skipped right over that denomination).