So where is some good data as to how much traffic can convert and how much CPM one can get with various types of traffic? I've been all around googling this to

So where is some good data as to how much traffic can convert and how much CPM one can get with various types of traffic? I've been all around googling this to come up with almost nothing. I know one must work on getting users first, but this is not always a viable method, and sometimes one must worry about monetization later on.