I never did buy things on credit, I always paid for 'em, because I can't see much difference in paying for something and just waiting a week and pay interest on it; that looks foolish to me.
At some point, I had to make a decision: I could practice more and become a really great guitar player or I could work on writing better songs. There are only so many hours in the day, and I found writing songs more fulfilling than working on becoming this virtuoso guitar player.