Is your internet allowance used when you play games dowloaded from Android Market?

[Thomas Whittle]

Only for multiplayer games, in-game advertising, updates and clicking through to the developer's website etc. If you have downloaded a game and are connected via WiFi it will not need to use your data, even if it is doing any of those things above. Sometimes apps can do things in the background (like update) even if you aren't using them. To be sure, just switch off 3G when you are not using it (ie unless you are actively using the internet while away from a WiFi connection).