Not an expert by any means, and on the few occasions i have used Ebay, i am normally outbid in the last few seconds anyway.
Now a couple of months back i wanted a Tmobile pulse 1 phone second hand, when i bid and set my max limit, i was always outbid regardless, and my max varied from £60 ot £80, which seemed the norm for these items.
My son decided to get me one for my birthday, he bid just the once for a phone with a high android running programme and won it for £66. these regularly go for at least £25 more.
His believe is that regardless of max bid, if you get your bid in at the right time and it is excepted and the clock runs out before the automated system can kick in with a response you win.
Maybe this is not the case but he has had far more success than I and any automated system has to have some sort of time lock for legal reasons,so I have strong suspicions that this could be the case.