[Hasz]

Realistically, very few things are totally passive. Even index funds, probably most people's idea of totally passive, still take work -- taxes, reading statements, etc. For most people, I think passive is reasonably defined as less than a 2-3 hours a week. I probably spend that amount of time looking at my portfolio.

Selling on Amazon or eBay is surprisingly streamlined. Exceptions occur, but they're pretty easy to take care of if you budget them into your margins and don't try to jerk buyers around.

I sold a few hundred dollars a week on eBay and a "problem order" comes up once a week at most. Usually, it's just a full refund or a new shipment.