I am brand new here but a long time collector and participant on
ebay (over 3,000 transactions since 1997). As a buyer, there are a variety of things that impact my behavior.
First. the vast majority of stamps offered on
ebay are buy-it-now. For example, I just search all of British Commonwealth and Colonies and found 263,219 lots. Of those, there are 54,196 auctions, which represents 20.5% of the total. The other 79.5% of the lots are buy-it-now. When I started on
ebay in 1997, 100% of the lots were auctions. The auctions are a lot more fun. The rest are just price lists, which can be found all over the internet and by mail.
Now there are some scarce items offered buy-it-now, but most are not scarce and sellers price a lot, perhaps the majority, at retail prices. I think a lot of buyers are like me- they don't go onto
ebay to pay retail. If I want to pay retail, I'll buy at shows where I can see the stamps and be sure I am happy with the quality. Or, I could buy from sellers who I know and trust from years of doing business where I know they will send me quality. And I know if they make a mistake, I can return the stamps and they don't accuse me of switching stamps out.
I cannot articulate how frustrating it is to receive hinged for never hinged, or stamps with tropical stains, tears, holes, and all kinds of flaws that are difficult or impossible to see in the scans provided, often because the seller has arranged the stamps in the scan to obscure corner, perf, and gum problems. Then I have to post them back at my expense and wait for a refund (even though I paid first and paid for the postage to receive the stamps). This is not uncommon- I would say 30-40% of the lots I receive from
ebay (and Delcampe) are lower quality than described, and every* seller swears they didn't look or didn't see or think I'm just a swindler. I have had better luck overall on BidStart, which I like a lot, but I still probably need to return 20-25% of items received from BidStart.
At times, I have given up buying from unknown sellers and I suspect other buyers go in cycles just like I do. But in the end, it's a hassle to send stuff back and lose money in the process.
I think if the philatelic community auctioned most items, and were super vigilant about describing conditional issues (after all, don't sellers reject items you don't want to sell? Buyers are the same!), I think the general trend in sales would be more positive overall.
I still buy stamps online- a lot of them. Hundreds of dollars just in Sept. But I don't come online to pay retail and receive stamps lower in quality than described and/or pictured.