Things I hardly if ever use because I can't hardly reach them !
I have online banking so I can check my balance at any time. You can also use an ATM to check. Remember, a debit card means that it's tied to your checking account; it's not a true credit card. So, if you've run out of money, you're out of money until you get paid again.
There should be a customer service number on your debit card. Its usually an automated system and will give you your balance. For online they should also give you the website on your card.