I don't buy pipes on eBay but I do from time to time bid on the only thing I can truly be said to collect (that is, a thing I buy just to own, and not to use): 19th Century fighting steel from around the world. American Bowie knives, French bayonets, Pashtun Khyber knives, Ghurka kukris -- that sort of thing.
I have a pretty good sense of what a given piece is really "worth," insofar as that means something withing this very little and odd marketplace. Now and then something comes up on eBay that appeals to me. I set an auto-bid at what seems like a fair price, plus maybe 10 percent. Then I ignore it. Utterly. I don't even read the emails that come in, until the bidding is over. I've done this perhaps a dozen times; I've secure the item four times.
Since I don't "have to have" anything so utterly unnecessary as a camel-bone-handled, highly engraved, still beautifully functioning, 205-year-old Bannochi lohar from near Peshawar, I have no psychic investment to lose if I don't "win" the bid. And if I do "win" the camel-bone-handled, highly engraved, still beautifully functioning, 205-year-old Bannochi lohar from near Peshawar -- and I did -- then it's a happy surprise.
I realize this post is a little off topic, and more joy and power to those who enjoy the elbow throwing of active eBay bidding. But it seems always to end in tears.