Christine Hennessey is almost finished paying off the 2014 Nissan Sentra she bought used in 2017. (Photo courtesy of Christine Hennessey) Unless you’re Elon Musk, buying a car is a pretty big deal. With the average price of a new car now topping $30,000, most of us can’t afford to pull up to a dealership... Valerie Lai is a writer at NerdWallet.