a.) go shopping in a town centre on their own (involves a bus or train journey)
b.) Go out at night on their own with their friends to the cinema.
c.) stay at home on their own
I'm thinking smallish town, not major a city centre with a reasonably low crime rate. I know this varies greatly from family to family depending on the maturity of the child and the area etc but I just need an idea of a reasonable ages.
EDIT: I'm setting this in the UK,