Even the cheapest, most basic cars are now ridiculously expensive to buy used

• Small economy cars aren't so economical anymore.
• Cheap hatchbacks and sedans are shooting up in value on the secondhand market, a new study says.

The market for used cars has been completely off the rails for what feels like an eternity now. And just when it seemed like things couldn't get any stranger, they did.

Now even the most basic, low-demand economy cars are soaring in value just like the rest of the secondhand market. Not only are these vehicles no longer immune to the inflated pricing, several of them have experienced some of the most drastic year-over-year value increases of any used vehicle, according to a new study from automotive research site and search engine iSeeCars.

As of November, the average used Mitsubishi Mirage will cost you $14,404, around 52% or nearly $5,000 more than it would have in November 2020, according to the study. A used Chevrolet Spark now costs $15,672, representing a $5,275 jump. The average secondhand Kia Rio has gone up in value $4,790 and now commands $16,135.

Those prices indicate people are willing to pay about the same for used Mirage, Spark, or Rio as they're willing to shell out for a brand-new one.

It's at least somewhat understandable that in this frenzied car market, popular SUVs and pickup trucks are going for big money. But these are small, cheap sedans and hatchbacks that, before the pandemic, nobody would have considered a hot commodity. They're the kind of vehicle that has been rapidly going out of style in favor of compact SUVs.

The problem, though, is that new cars are in short supply due to a computer chip shortage and other supply-chain related challenges. That's driven up the price of used cars to the point where even not-terribly-popular models are starting to look increasingly appealing.

More desirable vehicles like SUVs have become so exorbitantly expensive over the last year and a half that they're out of reach for many buyers, forcing people to turn to little hatchbacks and sedans, Karl Brauer, executive analyst at iSeeCars, told Insider.

"The small cars were the least bad deal, and now they're going up in value," he said. Interest in small cars bubbled up only recently, he said, once price hikes had already hit pickup trucks, coupes and convertibles, and then SUVs.

Rising gas prices may also be driving demand for petite, fuel-efficient models, Brauer said. That could help explain why the hybrid Toyota Prius and all-electric Nissan Leaf also made iSeeCars' list of the 10 used cars with the greatest year-over-year price increases.

The researcher also compiled a list of the used vehicles with the lowest year-over-year price increases, but it's not exactly reassuring. That list is dominated by expensive luxury vehicles — ones that are still shooting up in value, just not as quickly as the rest of the market.

According to iSeeCars, the used vehicle with the lowest price increase over the last year is the Volvo XC90 SUV. The average one will cost you only 9.3% ($3,619) more than it would have last November. Brauer stresses that this is not the way things should be.

"A car shouldn't be going up in value, except for really rare, unique cars and classic cars," he said. "From a purely financial analysis point of view, a new car is a terrible thing to buy."