If you can buy websites + database which is making $1200 a month auto pilot. No scam or fraud, but real website ( Pagerank 4 ) with real content and advertisers + affiliate links - total income = $1200 a month. How much will you pay for such a site ?
I guess it depends on the cost of running the site. I don't see "autopilot" type of sites as real business, so that will immediately devalue the site in my eyes. Now by "autopilot" you mean a well placed system where people working in the background that require minimum management, then it will lead to the next question: What is the potential for growth? Taking those figures into consideration I could make a hypothetical offer.
Depending on the structure of the business and the history of the site and it's age I would go as far as to pay a P/E ratio of 5.
Its normally recommended to take the monthly profit and times it buy several months to give you an idea of what the site is worth. However its like most things - its only worth as much as somebody is prepared to pay for it!