A satisfactory knife buying experience through eBay just requires reasonable care. Speaking just of factory-made production knives, a lot can be inferred by just the seller's or manufacturer's location. If it's somewhere in the world where a day's wages in dollars can be counted using the fingers on just one or two hands, this goes a long way to explain an absurdly low asking price.
Don't be shy about using eBay utilities to ask the seller to clarify some point or to address an issue not explicitly stated in the item listing. It goes without saying that an honest seller will welcome such queries, and it should be equally obvious that a disrespectful response or no response at all is a pretty good indication you should choose to spend your money elsewhere.