I have heard the opposite from other sellers. I think it may vary geographically - my own personal experience is that it is actually quite expensive and cuts significantly into what you make. Further for if you use Amazon fulfillment you have to pay them for storage too.

Some of these opinions may be coming from people who don't have a lot of experience actually running a profitable business on a day to day basis. There's a world of difference between selling something on Ebay as a hobby and actually having a business.

I can make a much better hamburger for less money than what I can buy one for at McDonald's. That doesn't mean I can run a profitable international business that employs tens of thousands of people.

I can't speak for the rest of the world but I can get some pretty good deals on restaurant equipment here in Murica buying it from failed restaurants. Being able to cook isn't a guarantee of success.

And I minimize the Amazon storage fees by monitoring my inventory and only shipping adequate quantities when they're needed. I have made mistakes and ended up paying long term storage fees, but I learned from my mistakes before it ruined me.

And, with that said, I'm selling out the inventory that I've got at Amazon and closing up. It's the competition who can buy in huge quantities at a much lower price that's taken the profit out of it for me.