First, I don't use BIN on most of my items. Those where I do use BIN, have a history of recently sold prices. I will put my BIN price somewhere in the middle of those that have recently sold. Unless there aren't any others listed at that time, then I will list it towards the higher end of the recently completed sales listings. When I sell, I want to move this stuff, not sit on it.
If you've read any of my posts on here, then you see the kinds of things I sell. An eclectic mix of things. from vintage glassware and pottery, to militaria and ephemera, to vintage toys and games, to perfumes and jewelry, and everything in between. Basically anything and everything that is small and collectible, I will buy and sell.
If it's an unusual or rare, htf item, thats one thing, but I see items on there all the time with crazy, unrealistic prices. Makes me wonder, what the hell these people are thinking. I can't stand people that go out of their way to try and take advantage of someone.
I will start on the high end on certain things, the low end on others. If I don't have a comparison, I will list for what I think someone would be willing to pay. Or if it's really rare, i'll list it for .99 and let the bidders decide. I have never been disappointed when selling one of my own items, as far as the final selling price goes. Why? Because I don't list anything for less than I would be willing to let it go for, even the .99 items. I ain't skeered.
In short, I'm not going to pay the highest price for an item that has multiple identical's for less. I'd be a fool to do so. I guess you sell mostly coins. They are a different animal because each one is specific in it's condition. As such, prices will always vary greatly.