I have 4 rims and tires with center caps for sale. They're in very good condition with only one rim having one curb rash. The tires are older and probably need to be replaced. I think $400 is a fair price in this condition. Can send pictures if interested. I'm located just north of Birmingham, Alabama.
The price sounds fair for Challenge wheels but with tires they will be too expensive to ship. I would suggest getting them dismounted.
It's outrageously expensive to ship wheels with tires on them. I couldn't afford the shipping on some 16" wheels with tires a few years ago. As I recall, the shipping would have been almost as much as I paid for the wheels. Without tires, the shipping was reasonable.
Tires would probably be a bonus if you sold the wheels locally.