do i need a bank account for a debit card?

I balt a $3 Temporary debit card and asked the Wal-Mart cashier to put a curtain amount on the card. I gave her the money and she told me to call the number on the recipt to activate the card. Can I go ahead and use the money and not have a bank account. Plus, do I need to spend all my money before terminating the card or will I get a check for the amount left on the card?