That's probably because the people you can ask who fully understand the procedure you need don't know what the prices for you are or everything you're going to need, and the people who know the prices aren't doctors and couldn't determine what exactly the procedure will entail. This is by design, of course, but it means that the people you might try to get a price from aren't able to tell you, even if they really want to.

Take your car to a mechanic, and ask how much a repair is before they look at your car. They can tell you typical costs, but can't tell you what your repair will cost yet. So you let them look the car over, then come back to you with an estimate. But that's still not the final cost, because once they start working something else might come up, and they'll have to stop to talk to you about the additional work. You don't know the final cost until all the work is done. That's the way it is with medical procedures too, except most of the time you can't stop midway through to discuss options and costs when something unexpected happens. The doctor just has to take care of it, and let you know about it afterwards.