Suppose I have a game for purchase on Android Market; is it possible to allow the buyer to send a limited amount of invites or codes to their friends, which will allow them (the friends) to download the game free of charge?
Or is my best bet to make the game free and use in-app purchases and/or codes for account creation (it’s a network-based game)?
Unfortunately there’s not way to let a user install a paid app for free (presumably in case it’s exploited to cut Google out, thus costing them their 30%)
Your second option – a free app with in-app purchases – is by far the better option.