1) support costs for themselves (if they can't go back to the parents, this is of course a lot more than it would have been had there never been an intervention)

2) (if applicable) education costs (including the need to go for more expensive education due to age. For example, going for secondary education when already 20 years old costs a lot more than doing it at 15)

3) lost pay. This is years that they cannot work and earn, and counterintuitively this is the pay of the LAST years they're working

Of course CPS really prefers offloading all the usually massive costs of their "help" onto the children.