There is a marketing strategy called "loss leading' or "loss leaders" The strategy works like this, you list cheap items with free shipping, essentially trying to make the deal look too good to be true, offering a crazy cheap bargain so someone will buy it. On the sale, you then have their contact details which you can now market to them direct outside of eBay and promote your own website where you in turn hope to then convert that customer into regular customer, which you can then make money from in the end game.
It's also called "setting the hook" You have to be prepared to take the loss in the hope that you get a longer term payoff. So anyone can certainly do it, but you can never make short term money from it lol, it's all about running at a loss. Think of it this way, when you have a marketing budget, you may have $5,000 allocated for newspaper advertising. Well, that's 5K you have accounted for to lose, so loss leading works the same way. You allocate x amount that you are prepared to lose to market your business in this way and away you go.
So what you are seeing is just good old fashioned smoke and mirrors marketing in action. Either that or the person has just decided to lose money for no reason at all, either is possible of course lol