Why I can't see the “price” tab in itunes producer
When you create an account on iTunes Connect in order to distribute books, you can either create a Free Books Account or a Paid Books Account.

Apparently, for the Price tab to appear in iTunes Producer, you have to be logged in with a Paid Books Account. Make sure you followed the right procedure when you did create your account. If you didn’t, I’m quite sure you can somehow switch from Free to Paid. I don’t know how, though.