Can one sell his BAR_METZRA rights to a non-neighbor?
As has been mentioned here many a time, Wikipedia is not considered a good source for accuracy in Torah related information. But just as a starting platform Wikipedia cites a dispute among the Rishonim whether Bar-Metzra is a right of the neighbor, or only an obligation on the seller, or on a non neighboring buyer.
The answer to the question may be dependent on this dispute. If Bar-Metzra is only an obligation on the seller, or on a non neighboring buyer, then the neighbor has no "rights" to sell. Only if we say that Bar-Metzra is a right of the neighbor, then there may be a possibility that he may be able to sell this right.
[Answer inspired by comment from DAVID KENNER]