I would say that what you paid was the right price. If it sharpens your razor properly then it is invaluable. I would suggest that you find a Mentor or someone in your nearby area to check out the stone and teach you how to use it properly. It is not lapped so it would probably damage any razor it was used on.
Go to the "Library" about and learn a bit about the process of straight shaving and how to maintain a razor.
Please add your location so someone maycontact you for a further help.
~Richard