The rules say "No paid games or games that require someone to pay in any way"...   

a) Is PWYW is okay? 
(since people don't have to pay)

b) What about if the game is free for a month or two after the jam ends, but costs a dollar or two after that?   
(and would offering community copies change the answer to this?)

The rule is designed to stop people using the jam as a way to promote their game that they made regardless of the jam's existence. It is also so that participants can play everyone else's game. 

The game should be playable for free by everyone who wants to.