Why don’t Seth or Ryan have a car

Just watching the ep where Marissa and Theresa have a little spat over who’s giving the guys a ride to school and it makes me think — why do they still not have cars?? All the other teens have them. They drive Kirsten’s car a lot. They clearly have licenses and are trusted to drive, and obviously they have the money. Why are they still going around on BMX and skateboard lol