I used to work for a private fostering organisation and we took children from all over the country - basically when local authorities had no places they go to the private sector to get a temporary home for the child - it is then the local authority who pay the private sector for that place - and Yes, it is more expensive than paying a foster carer registered with the local authority - not certain why this is but perhaps it is that the private organisations are smaller, they do all their own vetting etc. and can charge what they like!