Used-car prices are at their highest level in many years. Trade-in values of used cars have jumped significantly, especially for small cars. Someone trading in 2009 Kia Rio in good condition, for example, can expect it to fetch about $7,500 this month, up 17 percent from its value of $6,400 in May, according to the National Automobile Dealers Association Used Car Guide. That means buyers will see higher prices too, as much as 30 percent this month compared to a year ago. The supply is down because people stopped buying as many new cars three years ago during the recession. Highs may come down by August or September.