Even though the used car market , pre-owned cars are still in high demand. According to a recent study by certain vehicles are seeing some pretty dramatic price increases over the past month, while others have seen some fairly modest decreases.

According to iSeeCars’ data, the used car market saw an overall price increase of about 4.1 percent (around $941) from July to August. While a $941 isn’t a lot of money when it comes to spending tens of thousands of dollars on a vehicle, some cars have experienced price jumps that are fairly substantial.

Dodge Challengers saw a nine percent increase in the past month, with average price increases of around $2,600. This is interesting on a few levels. First of which Dodge makes a whole lot of these cars, so it’s not like they are difficult to come by. Though, of course, special editions like Demons have seen a jump in the pre-owned market so perhaps that is driving up the overall average.

Secondly, of the three muscle cars, the Challenger is the “oldest” in terms of getting significant platform or motor updates. Buyers in the market for some Mopar muscle might want to wait until the colder months when rear-wheel-drive cars historically aren’t in demand if they want to score a better deal.

At the number-two spot is the Range Rover Sport with an 8.9 percent increase which translates to a price jump of $4,226. What I find curious about Range Rover is that also pegged the Range Rover Sport as the fourth slowest selling car in the country. Units will sit on the lot for an average of 125 days, which is a long time for those of you who aren’t in the car-slinging biz. Perhaps there is a correlation between Land Rover dealers being overly ambitious with pricing.

Of course, most buyers want to know which cars are seeing price decreases in this challenging market, but it seems unless you are shopping for a Porsche 911 you won’t find significant savings by targeting the cars below.

Even with an average decrease of around $1,400, that is still only a drop of 1.1 percent for Porsche’s iconic sports car. That drop is likely only to apply to the more recent generation cars and anyone shopping for older models will find a market that is holding firm and sometimes increasing in price.

To see the full study check out .