When my two (10 yo) got their iPod touches in May I set them up with their own Apple ID but without a credit/debit card registered to the accounts(can be done).
This allows each of them to be given iTunes vouchers and they can spend them any way they want without arguments about who spent the money on what. Music is in a shared directory and they have their own libraries/playlists. They mostly just use free apps so there’s no conflict there.
They are going to want their own accounts sooner or later so why not do it now? Certainly seems to work well for us.
i have Voided apple for all these years and find it is slowly invading uphill towers.
There is a reason for this and I would rather it was this way than Microsoft.