18yo dd will be staying at home for at least the next 12-18 months. She will be 'working' full-time, but as an unpaid volunteer. She has a very small part-time job as well. Dh and I will be supporting her, and need to decide on an allowance for her. She will be paying for her own clothes and entertainment, but we will continue paying for her driving lessons. She will be expected to contribute to the household in practical ways, rather than financial, though she would pay for minor things like getting milk and bread if we run out mid-week and ask her to pick some up on the way home.
What would be a reasonable amount to give her?
(Before anyone tells us to make her stand on her own two feet, dd has additional needs that mean she needs a very gentle transition into independent adulthood, with a lot of support.)