Well i found this http://www.bonanza.com/booths/happyhourcomics/items/C64_Commodore_Model_1541_Test_Demo_Diskette_Disk http://www.bonanza.com/booths/happyhourcomics/items/Commodore_Vic_1540_Test_Demo_Floppy_Disk both 5$ each, free shipping wondering are these rare or not.
That could be seen as breaching this rule: http://www.assemblergames.com/forums/showthread.php?t=14035 Besides, if you don't know whether it is rare or not, perhaps you're best off asking in a more general forum.
Those are common as shit, the 1541 one more so than the 1540 one (I think I have one or two of the 1541 test/demos laying around somewhere). I wouldn't even pay $5 for one, maybe $0.50 for the pair? I'd honestly expect them to be thrown in free with a matching drive before I'd expect someone to pay $5. For the record, the terminology "test" and "demo" does not mean anything remotely close to what you might think in this context. These disks were packed in with every drive, and had tools like a DOS wedge, file copier, disk copier (for non-copypro disks), and a few BASIC programming examples.