I have always found bidding strategy and psychology on Ebay to be quite interesting as I see the bid amount on some items exceed their apparent value, especially when you can google the item and find it from an on line retailer for less.
I have seen bidding wars erupt and have been tempted at times to exceed my previously determined amount, especially when the successful bidder has beat me before in an cyberspace "Oh yeah, I'll show you" which makes the seller very happy. Same psychology that has people offering 500K for a house that should sell for $380K max.
I worked in a dive shop that was near a major Sunday morning swap meet in Socal drive in theater in the 1980s. We would always get people in with used gear that they had just purchased at the swap meet asking about servicing but really wanting reassurance that they got a good deal. Most of the time they got what they paid for. Sometimes they got took. Some people got great deals, but not many. Often, the shop, which also sold used rental equipment, could meet or beat the price and offer a limited warranty. I guess the only difference between today and yesterday is that on Ebay, everybody knows if you got taken to the cleaners and then go on line and tell everyone else about it.