One of the great things about Amazon's App Store is that its online interface allows users to "test drive" apps before deciding to download them. This functionality definitely comes in handy, especially when mulling over the decision whether to buy a paid app.
In an update to the App Store app today, Amazon – besides fixing a download bug and improving stability – introduced its Test Drive feature, meaning users can preview apps right from the palm of their hand before downloading.
If you've already grabbed the update but don't see the Test Drive button, don't fear – it seems that the functionality is being introduced in stages. It's also worth noting that the Test Drive feature is currently in a beta stage, so performance may not be perfectly consistent.
If you haven't got the update quite yet, just open up the Amazon App Store from your device and check for the update in the settings menu.