As far as making money on ebay... it's hit and miss. To do it all the time and reliably, well it's more often miss then hit.
Unless you were one of the "pioneers" that started about 5 years back or more and putting out products that had no competition, then chances of you starting to make money as an individual from scratch is very very low.
If you are already a business and have a REAL store to make money through and use ebay as another outlet to sell what you can sell on there, then yes, ebay is very profitable as another avenue of revenue.
The problem with ebay is you need a hot item and you need to get it at a price no one else can get it at. Then get it in bulk and sell it in bulk with little competition. Chances of you doing this are very slim. Finding hot items isn't that hard. Most tend to be electronic related. However, finding them at a price where you can resell them for more and make a profit and hoping no one else can do that either is another story.
I have a few friends that started back in the day and have a "niche" for certain items. One friend does B to D rated horror movies. He's the biggest seller on ebay for this stuff and does "OK" with it. Not well enough and stable enough to not need another job. It's still a side income for him. He does say there are other people out there that try to compete with him for this niche market of stupid, but hard to find, movies. These are the kind of movies that no store carries because if they did, chances are that maybe only a handful of people per town would buy them. Those that do are fanatical about buying them. But the demand is so low overall in an area. So ebay allows my friend to reach out to all the handful of people in every town around the world and give him a decent enough market. But still, it's a niche market.
My other friend does custom design work on pc's, xboxs, playstations, and other stuff with his air brushing and modding. He STILL needs a full time job elsewhere but it's a hobby that makes him money now.
In both instances, both friends of mine started way back when and have built up good feedback over the years well before others tried to compete. Now, both have to deal with TONS of competitors and they still do alright mainly because they were the originals. The other sellers for their niche don't do nearly as well because they just don't have the volume of feedback. Still, more competitors try to come in all the time. Many fail and give up all the time too. My friends do alright but not enough to live completely off their ebay dealings.
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