There are two convenient methods of checking your own account balances.  And when in doubt, you can visit the Campus Card Office in Engineering 313 during office hours.

VTS

Value Transfers Station (VTS) machines located in the USB lobby and near the west elevator on the 1st floor of the Student Center.  Just swipe your Campus Card, select the account and check your balance.  Nothing could be easier, except...

MySU

Login in to your MySU account, and select the Personal tab on the top navigation.  Check out your balances in the SU Campus Card section and then click the link to see your recent transactions!  Now that's easy and convenient.