Eligible for 10 Free Days - How does it work?

Basically that's it. If I'm eligible for 10 days and I can only get those 10 days by entering credit info (again)... then do I have to pay to get those 10 "free" days? Or will it be like I'm signing up for the first time again?

FYI: This is the 10 free days you get if you were once an active account. NOT the 10 day free trial.