Thats fine if you pay that much..but you asked what the market is for him now. There are loads of really cute dogs in shelters and rescues. And yes even nice ones. (A friend pulled a JRT pup of 4 months for me from the local shelter..just a gorgeous dog. She has gone on to win all sorts of racing events. Even at the Canadian Nationals) I asked the owners to make a donation of at least $50 to the JRTRO (JRT rescue) even though she didn't officially go through the rescue.
Pups are worth a lot because they are as close to a blank slate as you can get. Also if you paid more that 1500 you got ripped off. You can buy really good quality breeding stock for that price. What kennel did you get him from. IF his parents did things, like were top conformation, obedience, or agility competitors he might be worth 100-150 dollars.
But really the only people who would pay you any money for your dog are the sorts of people who buy dogs off the internet.