Before you buy that Android Application, you should know what the colors on the Android Market mean before you click the BUY button so that you know what you are buying in advance.
Blue – Books
Green – Apps/Games
Orange – Music
Purple – Newsstand
Red – Movies/TV Shows
It would be nice in the future if Google would split Apps and Games into different colors (ie. adding a yellow or black) so that buyers could differentiate a Flash app for use in the dark from a Flash game for the kids and kids at heart before digging deeper in to the details screen since moving from screen to screen will use Mobile Data if not on Wi-Fi.