Less then $10,000 for sure. Unless it has good content or a large forum and is fairly old (assuming it does $10k+ depending on the content). I'd say 1 year profit is much more realistic if its just and SEO page or a new site.
Your yearly revenue is $3600. Then we will have to look at how much time you spend on it per day to calculate a realistic "salary" which a hired person would get for the work.
For example, if you have to work (answer emails, update...) 8 hours/week, then to replace you, the hiring cost is $200/week (assuming $25/hour) - $10000/year. In that case, your business is really losing $6400/year and won't be worth much.
If you only need to work 1 hour/week, then your income is over $2000 after the "salary cost". Using 3 x yearly income, I would put the value at $6000.