I know I'm late in this game, mostly because I never access the Amazon Appstore for Android from my browser.
However, since I was writing my earlier post and viewing Amazon.com at the same time, I decided to flip over and see what the free app today was. It sucked. But, I did discover a cool feature on the Appstore called, "Test Drive."
This is a cool feature that lets you test drive the application on a generic Android device inside your browser before you purchase it.
Although I'm partial to the Android Market, Test Drive is one of the cool "set-you-apart" elements that makes Appstore for Android relevant.