Free apps or not, you cannot simply keep the status quo with a card with no funding. You must fix the issue before you can proceed.
Change or remove your Apple ID payment information - Apple Support
Free apps or not, you cannot simply keep the status quo with a card with no funding. You must fix the issue before you can proceed.
Change or remove your Apple ID payment information - Apple Support
A payment method is required even if the app is free.Payment methods that you can use in the iTunes Store, App Store, and iBooks Store - Apple Support
Can’t download or update free apps in App Store