It's generally a case of all of the above. Usually with large sellers, it's having a company and buying wholesale. They then don't have a physical front (or maybe they do) so can sell with little overhead. Then again (as with most vape stuff) it's coming out of China from the likes of FT, DHG and the like.
There are occasions where it is overstock or clearance stuff being bought up or maybe even auction buys from defunct companies. They do sell B stock as well, there used to be a store near me that sold only Wally World return items, so I'd imagine something of the like happens on Ebay as well.
Lastly there's the darker side of it, stuff that "fell" off the truck. Now there's no way to prove it of course nor how often it may be happening. I for one have no doubt that there are many items on there that are "hotter than a two dollar pistol" as the saying goes, lol.
The biggest issue is product validity and repercussion, which is very little in auction sites. A buyer is buying as is. Now sellers aren't allowed to outright lie but there is a lot of room for wiggle. Since the actual site (Ebay) doesn't lay hands or eyes on the product(s), if a problem arises, it becomes a he said she said game.
It then becomes more beneficial to a seller with many high marks, than to a buyer with less transactions. Think in lines of trying to argue a ticket in court, who's the judge most likely to believe? In effect it, no longer is the truth looked at but who "may" be more likely to tell the truth.
I rarely buy from Ebay due to the fact it is self policing, so Ebay has more to gain from keeping high volume sellers, as to siding with low volume buyers. In short it is a rigged system, you have a fairer chance of results by just flipping a coin, at least then it's a unbiased blind decision.
