A few years ago in my search for picking up a Big Ben etopps auto before Super Bowl XL, I stumbled upon an ebay seller who had sold one of these autos for a decent price. I looked at his other listings but none of them were etopps autos. Instead they were high-end sports cards, all with buy-it-now prices and subtitles under the titles of all of the active listing. Almost every subtitle ended with the same words: Don't Wait.
What made this seller's listings so appealing was the homework he did. He uses two third-party ebay search services that allows him to dig deep into ebay's completed listings - terapeak and price miner.
In the subtitle he will include what the card sold for in the past and his buy-it-now will be around 40-50% less. I keep this seller as one of my favorites because he gets to me even if the past sale of a card occurred 6-8 months ago. Without clicking on his listings, I can read the title and subtitle for all of his listings and there's usually one or two which tempt me.
I've saved him as a favorite all this time because even after two years, his business model works of ebay, he's successful and he's got a good source of inventory.
You don't have to look far to find his inventory source. It's ebay. He's nearing 5K 100% positive feedback. And this feedback is not from selling alone. What I do to sober up from a listing that looks tempting is I peruse his feedback from sellers who sold him the cards he's currently listing just to see what he paid for them.
When you do this, you can see who really bought the steals. You may have to go through a few pages of feedback to find the card you want but you'll see that the margins for this seller is there.
With all due respect to one particular etopps member who low-balls many listings, waxpackcity is a high-end moemule. They both do what they do well.