At the end of the day, that's capitalism for you. I agree that its annoying if say, there's an Amiga going for free on Amibench or something and someone gets their first in front of a genuine user just so they can sell it on....
One thing I have done myself is buy a job lot of something, take the stuff I need and sell the rest on...it helps make the hobby more affordable and remember you are sometimes taking a risk acquiring a lot of what could be crap.
The thing that personally pissed me off, is that there was a guy selling an A4000 on Amibench - I drove for 2 hours across Southern England to buy it for £50 - he said it had stoppped working. What he didn't tell me, is that some of the people who had been there previously to buy the Zorro cards he was selling had done a vulture act and taken the HD cradle and keyboard from the A4000. Now, I wasn't going to go away empty -handed so I reluctantly agreed to buy it anyway... but A4000 keyboards seem to be like gold dust :-(
{bleep}s