To be fair, all the older kids have jobs and need transportation to get to them. I imagine that they live in one of those outlying housing developments and have to drive to get everywhere.
Heather was given a car by her grandparents. Bailey bought her own car with money she had saved up. And one of the boys (I don't remember which one, I think Rex) saved up and bought the beater truck that they used to get the dirt from the creeper dudes house.
I really want to see the next episode and find out whether the Bruce's insurance covers Rex's hospital stay for his asthma. Or whether the $18K they had left over from the show's first season will be tapped. This is obviously going to affect whether or not they can get a house. I tend to agree with Todd on the house situation. When you are paying rent, you are just giving your money away. When you are buying a house, at the end you have something you own. So, if they can swing it financially, I think the house is a good idea.
I noticed in the first episode of the new season that most of the kids have settled into their new poorer lifestyle. The all seem to have really good attitudes about it and realize that THEY have to work hard and save up if they want something. They can't just get their parents to buy it for them.