I'm 22 and live in half of a duplex that my parents own (seperate entrance, 2 br, 1 bath, full kitchen, laundry room, living room). I pay $500 rent along with all other expenses (clothes, food, gas, part of utilities, car/med insurance, etc.) Of course it's not what I would wish, but I'm trying to do the responsible thing right now as I'm saving up to buy a house in 2-3 years. I hope to be able to put down a $50k downpayment.
Anyway, yes even though I live in a different "household" I technically live in the same building as my parents so I in effect live with them.