You are going to be paying at least $150 if not more if you are even going to be able to locate one close to you. You may be able to get one from the community sellers and you will pay well over $200 due to shipping.
Also there is also a very slim chance that your LFS can even get them. I have asked all of my LFS if they can get them and they haven't had them on there list of fish they can get for well over a year. Last time I a black aros in a LFS was over 2 years ago.
Good luck on finding one, but expect to pay a good amount of money for it. If I was you though, I would just go for a silver. I like them better than blacks whether the silver has drop eye or not.