There are a lot of missing details that could radically change the cost. Such as how many need to be done? What are the actual tolerances? What is the penalty for failure? How time critical is it?
If you only need one, and it's not too big a deal if it gets botched, you may get a local school or maker space to do it for free. But they won't be able to help you if it's a production run. If you need 100 of them tomorrow, with really tight tolerances, you may not be able to find anyone that can do it for less that $$$$$!
Just off hand, I'd guess about $10-$20 for one, but that is only a wild guess not knowing the time & tolerance restrictions.