Let's put it like this:
If there was some easy option, anyone would do it and everyone would be rich. Now, that's not the case.
Selling products on Ebay is a **** business, all about offering the lowest prices. Don't do it. You might make enough to buy a coinoffer deal at McD, but I would rather go for the money.
Each time you have an idea, ask yourself: "Is this something 1 mio people are already trying to do?" - creating stupid Adsense sites with crap content or selling products on Ebay is something everyone does because it's easy (and yet no one wins anymore).
Think out of the box! Think!