for those that don't know engines would a custom cam based on what a client wants fall into the cheap category.
A quality custom ground cam can be as low as $100 - $75 above a shelf cam.
Cams are often chosen badly the uninformed
I don't know if a custom cam falls into the cheap category because it is still more expensive than an in stock shelf cam. I do know that a client with an odd requirement may need a custom cam though. I know this doesn't answer your question-sorry. J.Rob