Regarding to the free iWork

So guys I am a little bit confused about this whole free iWork if you buy a new iPhone or a new Mac. So I've got a few question about this thing.

1. First of all what counts as new? Do I get free iWork if I buy an iPhone 4s?

2. How about do I actually need to have a new Apple account or just use an old one with a new device?

3. And lastly if I buy an iPhone do I get the iWork for iOS and Mac OS X too?

All replies are appreciated! Thanks guys:)