There are thousands of ways to start and eBay type Business but what you want to know is what kind of a business you want to run. In my opinion, if you want to just make a few dollars, than you can start selling products for other people, but if you want to invest into your business, you really need to invest around 600-$800 to make some real money! About 200-300 are start up costs and the rest will be to invest into tools to make some money!
Ebay business is not an easy business, but you can make money with it. You also have to be legitimate business!
Take a look at this link for a lot of free information on how to start your own eBay!
There are a lot of eBooks writen on way for you to make money on eBay. I suggest you take a look at this blog about free information to starting an eBay business before you spend any money. The reason is that all the information there comes from my experiance and I know it works.