One of the myths with online businesses is that you can start them without any investment. That is simply not true because every business requires some investment to start properly. The good thing about the internet is that you can start with a very low investment but do not expect this to be zero.
The first place is your own home. Go through the garage, basement, closet and other locations looking for what you do not need. If something qualifies as junk then rethink it, maybe it is not junk to someone else. If something is worthless in your opinion you might still get a reasonably good price for it on eBay. This is perhaps the easiest way to make money using eBay. Always take a good picture of the item before listing it because listings with pictures get better bids. Then you must write a good description for the listing and set a low opening bid. You could be making hundreds of dollars like this and there is hardly any work involved.
Selling eBooks is another great way to making money through eBay. These books sell quickly. You simply need to find a topic you are good at and write a book. Even if it is something as simple as fixing a computer, changing hard drive partitions, or tinkering with household items or cars, fishing, sports, literally anything that you are good at can be presented and sold in the form of an eBook.
Another thing is to become an auction manager. Some people have great stuff but shy away from auctions. If you can do the job for them then you can earn a good commission per sale.