the Gateshead Rov z”l once paskened that you can copy a tape as long as you leave out one song. The logic in this pesak would seem to have been that seeing as the item which is sold is the tape then as long as you did not copy the entire tape you have not ‘stolen’ the item which is sold. That was in the old days of tapes, nowadays this pesak would seem to not apply becuase
a) copying music is rampant and a threat to the parnassah of the people who produce music
b) as each song is sold seperately it is now possible to ‘steal’ a single song