Those Sonys are good. What colour is the wrapper? If it's a green one, then it was the last Metal-SR that was available only in US while the rest moved onto the Metal-XR. If it's the black wrapper, those are really good tapes. The price you mention is irrelevant because a Sony Metal Master cost 12$ back then and now they are sold for 50$ or more on the internet.
There is no such thing as an unfixable cassette deck. Depending on your location, I can recommend a number of good service technicians that would bring your Nakamichi back to life.
I am considering of getting a Nakamichi as well because I never really had one and the awesome 600 series was released long before I was born.
Hi R. Daneel and all Audio Circle members.
Please find below one of the eight (08) cassettes I have.
Wow ! I did not know that I had a little fortune on my audio shelves.
I don't think I will offer them for sales,
because one day I would like to get my Nakamichi fixed.
My location is on planet Vietnam.
Here they cannot repair it, as a matter of fact,
they made things worst by loosing a little belt for the time counter.
May I ask you to give me one or two names of good, honest,
knowledgeable technicians that can fix my Nakamichi BX100,
the problem as something to do with the belts
and/or the pulley(s) according to the Vietnamese technician.
One day, I will go back to my home country Canada
and get it fixed so I can record some music,
because with vinyl, cassettes can last a very long time.
I have some VHS cassettes that were recorded more than 25 years ago
and they still play fine.
Waiting for your recommendations.
Thanks.
Guy 13