My first month being a part of the Amazon FBA program has been a total disaster. The fulfillment by Amazon program is where you supply the monster website with physical products where you hope to leverage their incredible marketing machine to make some extra cash.
I know someone who is part of this program and has been really successful. This person was super generous and gave me all the tips I needed to get started.
I decided to start mainly with books. You can get some really great books that sell well on Amazon just by visiting any bookstore or thrift store. The idea of course is to make a bit more than you sell it for.