Hello manshms,
Thanks for reaching out in Apple Support Communities. We're happy to help.
It sounds like you want to use your own payment method or Apple ID account balance, even though you are a part of a Family Sharing group. Take a look at this article: Family purchases and payments.
If you are a family member and you have your own Apple ID balance on your account, your purchases can be charged to your personal Apple ID balance. Apple Gift Card -- Buy an Apple Gift Card. Redeem your App Store & iTunes Gift Card -- Once you’ve purchased an Apple Gift Card, you can redeem it to add the funds to your Apple ID. Check your Apple ID balance -- You can always check your Apple ID balance to make sure there’s enough funds for a purchase.
The article Approve what kids buy with Ask to Buy is something can be set according to the family member.
Let us know if you still have questions.
Have a great weekend!