Guys, I think the problem is that most people who are looking to start up something on ebay or any other internet based business come into it with minimal understanding about how internet business is conducted, from A-Z. Usually they are in a financial bind and are truly desperate to get some cash inflow as soon as possible. In their frustration and desperation, they look for anything that sounds like it will deliver the big bucks they need.
Reality is that while there are clearly differences between internet based business and selling goods or services out of a storefront, the commonality is that you have got to go into any new business with the frame of mind that you may not see a real profit for 6 months to a year. At that point, it is usually pretty clear if you are making substantial progress, or if it just isn't going to work this time around.
So my advice, plan carefully, from the research you do on every single aspect of running your business, to the business plan you MUST have, to the realistic finances needed not just to start up the business, but to get through those leans times while you are waiting for things to really pick up. If you are selling solely out of a web site you better be prepared to lay out some decent cash money to get your site as far up that Google search page you can, or you are just invisible.
Above all, as Jimmy is so passionate about saying, think outside the box in terms of selling venues. START SMALL, sell low dollar, things you have around the house to build up experience and feedback. Find ways to get yourself involved with groups on line that may have an interest in what you sell or offer. Find groups that sell similar things that are open to working together to promote each other in terms of links and the like.
Okay, I gotta get back to work. I love to work. It is a sickness. But I love it. Good luck. When I think of more to add I'll be back.