The only "right" answer is: What someone is willing to pay for it.
I recently purchased an adult business for something like 5 months of turnover (not profit), because I felt it had potential.
If you are selling a bunch of affiliate websites, I would never pay more than 3 x monthly profit. Because usually, most of that stuff being sold is crap. But some might want to pay more, so it comes right back to where I started: What people are willing to pay
