There is no spiritual credit card but, in a sense, there is spiritual credit.  The spiritual gifts that God offers us do not have a price other than our commitment to do His Will, but sometimes we ask for other things.  A common example is what is often called spiritual healing even though it is the physical body we want healed.  Because of the nature of the material world we live in, anything we get in this world has a price.  When a healer uses spiritual energy to heal a physical there is a price to pay, a debt that ensues.  That debt is usually paid by the healer by getting a shorter life than she would otherwise have.  That is why healers shouldn't be healing people willy-nilly, but only when they feel it is really necessary and they can't teach the person to heal them self instead.  
    Healing is not the only way to build up a spiritual debt.  When we ask God, the universe, the powers that be, to help us in other ways, we may be accumulating debt.  When we harm others who don't deserve it, we accumulate debt.  This type of spiritual debt is usually called karma.  But karma doesn't have to be negative, it can also be positive.  Like making payments on a credit card or putting money in a savings account, we can pay some of those spiritual debts with positive actions such as helping others, teaching others, and forgiving others their karmic debts to us.  Those things can pay off our karmic debts to a large extent and sometimes even leave us with savings rather than debt.