Randy Alcorn gives some good thoughts about making sure we give to God even when in debt.
Here's a paragraph that stuck out to me:
Through debt sometimes we unconsciously try to maneuver God into a position where he’s obligated to “provide” in the form of our future payments. In a role reversal, we set up the rules of the game and then expect God to play by them. Assuming the role of Master, we demote God to the obedient genie, who exists to underwrite our causes and fulfill our agendas. In such cases debt is not merely unwise, but evil.