eBay may not be the most reliable source of tubes, but, there are not that many alternatives. I can't run down to a local tube shop. It is also hard to determine if the seller is intentionally ripping off the seller. It is almost impossible to determine what is meant about a tube testing good, even when the tester and value is mentioned, because of differences in calibration of machines and because most testers really don't give much meaningful results (they don't test tubes under full power stress, for example).
Ripoffs work both ways. I know someone who sells tubes on eBay that, on quite a few occasions, the buyer complained and he took the tubes back; the return, however, was of different tubes.
Ripoffs work both ways. I know someone who sells tubes on eBay that, on quite a few occasions, the buyer complained and he took the tubes back; the return, however, was of different tubes.