The answer is, you do both. You should tithe as a way of thanking God for his goodness to you in your time of need. If you forget the Lord, or if you think that your debtors are more important than the Lord, you are setting a wrong priority in your heart. Certainly debts need to be paid, but you must honor the Lord first. So give a tithe to the Lord and then pay your bills. I think you’ll discover that you can do more with 90% than if you spent the whole 100% paying your bills. God honors those who honor him. See To Tithe or Not to Tithe.