Do I need to top up my wallet before I can create a game?

No. You can create games with a zero wallet balance; no deposit is needed, for cash games too.

Creating a game is blocked only when your balance is below zero, for example after Playbox commission for completed cash games was taken from your wallet. Then top up at least to zero and create the game. The same rule applies to recurring schedules: with a negative balance they skip creating games and notify you.

The commission itself is taken from your wallet only after a game is completed, never when you create or publish it.