Cheapest option, PD, remains back-up plus Ranish, but remember that the space available AFTER re-partition will always be filled, and the OS partition you created will always be too small.
You/they will need to keep 'eyes' on the filling-up of the disk. Copy it off to a
RELIABLE DVD disk asap.
As suggested, external storage (or web if you have an ISP that offers that?) may be an idea.