I always buy them locally, since the shipping itself from DE or wherever, costs as much as the LEDs. However, there was a recent thread (and probably many other older ones) where a user bought them from ebay and they were alright, no errors or other issues. The ebay item link was there too.
Overall, you can buy any LEDs set for E53 from ebay, just as long as they are error free and they have no flickering. You could ask the seller prior to buying.