1. As long as you pays > mini, it is the same. So it is better to pay off because you don't have to pay the interest and financial charge, then.

2. 申请店里的信用卡是不是对信用记录不好？ Not necessarily. It is the total borrowing power (the sum of your credit limits) that matters. So yes, 信用卡的limit过高不好. But 申请店里的信用卡 really depends on the credit limit that they give you.