You’ll want to purchase one which is fuel efficient, going on the assumption that your teenager doesn’t have a lot of spare money.
Safety is key, so look for a car with amazing safety features. I would recommend spending the extra money for a new car when possible, as they have gone through more stringent safety tests and are likely to last you longer. However, one’s that are second-hand can be just as good. Buy from a dealer like ours for peace of mind as all our used cars come with a 2-year nationwide warranty.