Scum like this will always be around. It's not just on EBay, there are also those with seemingly legit webpages peddling the work of others for financial gain because these leeches are not good enough to trade themselves.
How can it be combatted? By those of us more experienced pointing out when some gimp opens a thread proffering the the latest holy grail for $99 (discounted from $399, but only until midnight

) is actually a totally free system and can be downloaded for nothing.
It kinda ruins their credibility when people realise they are being royally ripped off.