There are two boxes labelled 'Stake' and 'Win' at the top of the bingo window.
The Stake box displays the value of the bingo tickets you have selected/purchased for the game currently playing, or about to start.
The Win box will accrue the value of any bingo winnings you may accumulate during a bingo game. (i.e. In 90 ball bingo, 1 line, 2 lines and Full House or Bingo)
At the end of a bingo game, if you have won one or more prizes in the bingo game, your Win amount will be credited to your account balance and both the “Stake” and “Win” values will be reset.
Please see the help section on Currency Display and Conversion for more information for non-GBP currency accounts.