Cost of Living for a family of 4 in the GTA (Toronto)

How about the cost of Living for a "typical" family of four in terms of net income required to get by. I know there won't be a clear-cut answer, but given the fact that anyone returning to Canada will most likely be occupied in an entry-level position (i.e. no Canadian experience) what amount of net annual income do you think could be enough. The way i see it, if both parents have the minimum income (approximately Protected content parent/year) things are going to be very very tough (I believe Protected content almost half the money required to just get by).
Thanks in advance