Hi Audrey
Copywright in this country is a minefield.
I would have thought that if you had bought them legally from a proper source, then if you no longer need them then you are well within your rights to sell them on.
Personally I refuse to pay £17.99 for a disk when in the original catologue from technote they were from as little as £9.99.from the original Technote range. Especially, with the KN7000, with a little effort you can quite easily make up your own to suit the music you want to play.
It has to remembered as well that 'Technics' and 'Technote' were not one and the same.
This is not to decry the excellent standard of disks which Neil has spent a lot time producing for the Kn range.

Regards
Peter B