When I was that age and on the dole, (I'm quite old 
) my DM charged me 1/3 of my income, based on the fact that we were a family of 3. But, she always helped out with bus fare to interviews etc.
By the time I started work, she had left my (not so) DSF and we were living together in a small 2 bed flat. I paid 50% of all bills.
TBF it stood me in really good stead and I learned about budgeting, how much housing really costs, which I wouldn't have known without it, which was good when I moved in with DH and the hard work re money and budgeting really started. I have never asked for help, and neither has DH from his DP's. We were very poor, Ok now but still not well off.
DS1 left home by choice, not argument, at 16yo, got a place with a friend, got a job, and has always supported himself since then. He has never asked for help, but if he did we would know he needed it and do it.
When DS2 started full time work with a good wage, straight out of school, we worked out what a bedsit in our area would cost, deducted the cost of a lot of food that he bought due to his job, and he paid what the bedsit would have cost. He saved enough that 1/3 of his student loan is already paid off, and he is so much better at budgeting at Uni than his housemates, he is known as mintedDS2 but we don't support him financially at all now, apart from paying for his train fares home.
DS3 is only 15yo, but already has a job lined up for when he turns 16yo. He cant start before then, due to legal age restrictions.
Moral of the story. Learn financial independence/responsibility early, even (especially) if forced to, learn well, even if you are forced to and pay your bills.