If a listing is too good to be true -- such as a new item that is selling for a fraction of its retail cost -- that is certainly a warning sign. And if a relatively new seller is suddenly selling thousands of dollars worth of multiple quantity listings at fire sale prices with free shipping from overseas with extended handling times and very long shipping estimates, you should be very concerned, particularly if the items are expensive electronics, cameras, musical instruments, tools or outboard motors.
In general, you can avoid a lot of headaches by choosing to purchase only from established sellers that have recent and past positive feedback as a seller for selling items in the same category that you intend to buy. If someone is selling a dozen apple watches, but has no feedback, or only has feedback as a buyer, or only has feedback for selling dress patterns or fishing lures (actual examples I have seen), perhaps wait until they have a track record of positive feedback for selling electronics before you buy from them.
Some scammers have gotten cleverer -- and now appear to be completing a few phony transactions using low or zero feedback accounts to provide positive feedback for their most recent scam items. If you know what to look for, this is easy to spot. Particularly if the seller has just sold a few dozen items in the last couple of days and has already received feedback. In some cases, scammers will provide incentives for buyers to provide feedback immediately to entice other buyers, so if you notice red flags, do not assume everything is legitimate because there are a few recent positive feedback ratings -- look at the overall pattern of seller behavior, and how long they have actually been selling such items.
You might miss out on a good deal from a new seller once in a while, and nothing can guarantee that you won't still run into a scammer anyway, but you can avoid a lot of potential problems by choosing to do business with established sellers. Anyone can put together a listing that looks nice -- it is not hard at all to simply copy an existing listing -- but it is much harder to create a history of consistent sales and positive feedback.
eBay can close the scammer's account and refund buyers, but eBay cannot actually "fine" scammers and make them pay. When scammers are kicked off eBay, they often create new accounts or hijack other accounts to promote the same scams again and again.
