Q: Using own credit card instead of the family shared one

Hello lakilevi,

With family sharing setup the only credit card payment that can be accepted is the Organizer. However, that does not mean that you still can pay for items. The way that would work is you would need to purchase an iTunes Gift Card and redeem it on your Apple ID. Once that is done, the Gift Card balance is charged first and any remainder would go to the Organizers card. Take a look at the article below for more information. I have also provided links on how to purchase as well as redeem iTunes gift cards just in case you need them

Family purchases and payments

http://support.apple.com/en-us/HT201079

iTunes Gift Cards

https://www.apple.com/itunes/gifts/

Redeem and use iTunes Gift Cards and content codes

http://support.apple.com/en-us/HT201209

Regards,

-Norm G.