Yes hub dynamos are expensive. Especially here in the US where they are not that popular. But you find them in Europe almost anywhere. I have a few bikes of mine equipped with hub dynamos and purchased the dynamos and even complete wheels in Germany and brought them back from my family visits in Germany. Some dealers might even ship to the US.
If you don't mind side mounted bottle dynamos but don't want them to mount on the carbon fork you can also mount them to the rear wheel if the frame is not carbon. One of my bikes has a rear mounted dynamo. You just need to make sure to purchase the correct model. There are clockwise and anti-clockwise turning models. They all generate about 3W and are sufficient to power the modern LED lights.