If you are going to be selling on eBay and you are brand new I would suggest selling a few items around your house that you want to get rid of to start off. This will give you some practice and experience before you jump in head first with a wholesaler or dropshipper.
You will then be able to take any product and see if you can compete on eBay.
Once you find the product you then have to make sure the source is legit which you can do right here on Salehoo by asking. After awhile you will learn to do your own research as well.
One final word of advice is to never take a reference as fact from anyone but do your own research to see if you really can make a profit with the above tool.