I came into some extra stuff last year, collecters items, mostly. So I got an eBay account and sold some of it. It went OK, no complaints or anything like that.
After not selling for a few months, I put up an auction for four silver eagles which were slightly rare. Just after I posted it, silver spot dropped, and I had the starting price at spot, so they didn't sell. But I got a notice from eBay/PayPal that my account would now have a hold on it. It would take a couple of weeks to get paid. They didn't specify exactly why, just that my account activity was reviewed, and they decided to put the hold on it.
My guess is that they thought I might have sold my account, with 100% good feedback, to some con artist---because of the type of items changing to bullion coins for that one auction, after inactivity for a few months. But it also said that I would get paid immediately upon positive feedback from the buyer, for each auction.
They also raised their percentage charges around the same time.
So, for some things, especially stuff that people expect very low prices, like at the fleamarket, and with the shipping charges especially for heavy items, and the cost of packaging, eBay just isn't practical. Has anyone notice the price of boxes at places like Staples and Office Depot?---Totally off the charts! And packing popcorn? Or bubble wrap?---Sheesh! The best place to get that stuff is U-Line, they sell in bulk, and even with the shipping charges to receive it, it's still way cheaper, with good quality and service.
But for lightweight, small size stuff, if there is a demand for it, you can still make some kind of profit there. If you make bullion bars, or even buttons or blobs, they seem to do well also, getting above spot. There are some people on here who sell their PMs on eBay, and I haven't heard about any ripoffs yet, but I imagine it could be an attractive category for scammer buyers. (I won't even mention the "scrap gold items" or the eScrap junk that other people put on there! That doesn't figure in to my idea of "business.")
So right now I'm thinking, some kinds of stuff works OK, other stuff is only break even, and yet other things would only take a loss.
There is a way to search "Ended Auctions Only," and you can see all ended auctions, most recent first, and see what's selling and what's not, with the prices asked and highest bid. Or you can search the same way for categories or even specific items, and see what they last sold for, or didn't sell for. Some things seem to be seasonal, too. But you can pretty much know ahead of time, if it's worth it to post certain things.
Then the scam artists lower the appeal of the whole thing. I think the end result is that there are only a few categories that are worth using eBay for. Interestingly, those categories seem to be least affected by scammers, too.
