If you buy something with a debit card with no money, the transaction will almost always be declined due to having insufficient funds.
Although in some cases, the transaction with your debit card might go through if you have no money in your bank account, but will result in a $35.00 or more overdraft fee depending on how your bank account is setup and your bank.
Although by default, banks are actually required to decline purchases that you make with your debit card at the register if you do lack the funds.
However, if you have opted into an "Overdraft Protection" or "Overdraft Privilege" service, your bank will cover the purchase with your debit card, but will also charge you an overdraft fee, which is often around $35.00 for the negative balance.
But just be prepared that if you try to buy something with your debit card and have no funds in your bank account, that the debit card transaction will almost always be declined.
So in short, your debit card will almost always in 99 percent of cases be declined if your bank account has enough money.
You won't be able to buy things and some banks and credit unions have overdraft protection but if your bank account does not have overdraft protection, the debit card transaction will be declined.
The overdraft protection allows you to use your debit card even when there's not enough money in your account, but also gets costly.
Overdraft fees occur when you don't have enough money in your bank account to cover transactions.
These overdraft fees are often pretty expensive and can vary by bank, but most overdraft fees cost around $35.00 per transaction.
And these fees can also add up very quickly and can have ripple effects, which are also costly.