Without paying, you also lose Zeppelins and Submarines, and it seems all the players are assigned nations at random instead of being able to choose. Still a cool game for free, though.
When are we starting our game?
EDIT: For the record, if you are playing for free but some of the other people you're playing with pay, the ones who pay can get some perks/advantages that the guys playing for free can't access. Nothing big (for example: planes, zeppelins and subs are only available in games where everyone playing pays for the game) but little stuff like building units a bit faster and stuff. If we start our own game, I'm assuming either none of us will pay or if someone here already pays, they won't use those bonuses to gain the upper hand over the rest of us.