When I first got my license- I used either my mom or my dads car. being that I was the youngest- I didnt have to run my siblings around etc..
while using my their cars- I did not pay for anything, except sometimes gas.
When I was a senior- I bought a brand new car. I was working fri/sat/sun waitressing, and had saved up a huge $$...my dad co-signed for me, but I had to pay EVERYTHING that came with that car.
From that point on, I have had a brand new car every 2/3 years and have paid for it all.
DH's parents bought him/brothers cars, paid for insurance, gas etc... however they all worked in the family business making way less than comparable help, so it worked out.
Our kids are about 8 years from this, so we'll see what happens, though I do like the idea stated above, making a payment or paying for upkeep, either way its a wash..I think they'll end up wth fairly new cars...though, they'll pay for gas
Brandy