For a first couple games, I’d play with no bid at all. Have one (side/team/person) first play one side and then swap sides. That will help the players involved learn just how much bid they want to have in the future. Bids are more for when competitive players who know how to play the game sit down to rumble. If you just want to play a game one off, just have the experienced players play the Allies and the inexperienced play the Axis.