eBay is fine. They went through some bad times when they thought they could keep raising fees and doing whatever they wanted with no consequences. They backed off of a lot of that when many of their sellers moved to Amazon. Now the same is happening with Amazon and a lot of sellers are starting to move back to eBay.

eBay is wonderful if you play the game right. You get at least 50 free listings a month even without a store. Final value fees are reasonable for things under $1k. They do have a maximum fee cap, but it's way too high for something like a pinball machine. As a buyer, it's not hard to earn $2000 a year in eBay Bucks. That's free money! They do so many 10% bucks promotions and the occasional 10-15% off one item promotion that great deals exist.

The good old days weren't that good. I used to sell music CDs. They didn't have a catalog and you were only allowed one picture per listing. If you wanted to say what was on your CD, you typed in all the tracks yourself. If you wanted more than one picture, you hosted them elsewhere and linked to them from your item description. The only thing good was that postage was 1/3 of what it is now.

The marketplace as a whole is a minor miracle. Could you imagine 20 years ago that it would be possible to sit at home and make 6 figures or more a year buying and selling stuff online? With a little ambition and a lot of hard work, you can make more as a high school dropout than most people with degrees make. I work a full time job as a software architect, but thanks to eBay and Amazon, I'm going to be able to retire 20-25 years ahead of schedule. That doesn't suck.

If you know what you want and what you'll pay for it, set up an automated search to check for it every X minutes and send you an e-mail when it gets listed. The best deals sell fast.

A lot of the big money is in arbitrage. I know dozens of items I can sell on Amazon for $250-500 that I can get on eBay for $75-150. Some turn up on eBay once or twice a week, others just once every couple months. I have automated searches set up for about 200 items that alert me when they get listed in my price range.

I also sell some stuff I got from the manufacturer a few years ago. Those things generally bring in a steady $5-10 profit each, but I'm leaning more and more towards the higher priced items that are profiting $100-200 each. Less work and more money.

Most stuff on Amazon is gated now and it's tough to get approved to sell there. I sold used music CDs for about a decade there. Now if I try to list one it says I haven't been approved in the music category (not that there's much money in CDs anymore). You need invoices showing large purchases and many categories cost something like a $2000 fee to apply to sell in. It gets tougher every year, and you have to follow the rules absolutely. A suspension there lasts a lifetime and you can't just open a new account.

Anything sold for a profit is taxed, whether it's sold on Craigslist, yard sales, eBay, Amazon, etc. You have to do something like 200 transactions and/or $10000 in sales for Ebay/Paypal to report it. Even if they do report it, if you're selling personal items for a loss, just claim your cost basis and you won't owe anything. It's not an Ebay thing, it's a tax law thing.