I always carry a credit card unless (?) in case (?) I don’t have enough cash?

Was ist richtig? DANKE!

I want to apply for a student credit card, but I know nothing about APRs and interest rates. Help?

I want to apply for a student credit card just in case I need money while I’m in college. My mom and my sister told me not to but this is something I want to do on my own and see if I can handle it alone. I work 2-3 days a week starting Sept. [...]