What's your credit score? I think you're confused w/ building credit & accumulating credit.
"Building credit" does not mean accumulation bankcards w/ large spending limits...in fact, the more available you have the lower your score, whether you have them maxed-out or at a zero balance. Banks look at what you currently have & base thier lending on it, large credit lines are considered debt to lending institutions whether you use them or not...lowering your credit limits will increase your score, it's a fact. Also, making on-time monthly payments will increase your score...it shows the ability of repayment & giving the lenders confidence in that ability.
Assuming that the statement you made about never making a monthly payment in your life is true, then you would have no idea what a credit score is...
So what kind of car do you drive anyway?
Russell...make payments until it is no longer 0%, but at least show some payment history. As long as you are well w/in your means, the score will take care of itself.