The free spot on a bingo card is typically located in the center square and is automatically marked as "free" for all players. This space provides players with an immediate advantage by giving them a number that is automatically considered marked off, making it easier to achieve a winning pattern.
Although we understand that there is no money involved in the particular game you refer to, even so, participating in the bingo session would be against the spirit of Islam for the following two reasons: Firstly, it creates suspicion of gambling, and Muslims are taught to avoid places of suspicion.