It may be just me, but I don’t trust ebay. Too many counterfeits/scams/ripoffs.
Well, it’s absolutely impossible to rip you off on ebay when you pay with paypal, buyer always protected and full refund always guaranteed by paypal buyer’s protection.
There are no conterfit of old Dynavector cartridges, but i suppose you know what is Dynavector and you can recognize it, i had 4 different models, two NOS from ebay. I have returned one cartridge for full refund when i realized the cantilever is a bit off-centered, return shipping has been covered by paypal, so no loss at all.
If you prefer to buy cartridges from audiophiles on audiogon it is not a problem, but not as secure as on ebay with paypal.