People are here throwing numbers off the top of their heads without even reading the OP If it has been making money for only the last 3 months and the site has 4 pages then it will make 3-6 monthly income. I have listed similar sites on Sitepoint over the past few months and they sell for an average of $500-$600 so I'm speaking from experience. The site hasn't been making money long enough to be worth any more than that.
I tried to sell a site of mine (a forex site) for like 4 times monthly revenue because I want some holiday money... but people didn't believe that it was making me money. Fool's on them becuase I made $150 with it yesterday so I'm glad I didn't sell it Why don't you post the link and the traffic stats and you'll get offers from people. Normally, the market will decide how much a site is worth.. and you can't argue with the market.
@jm55: Wow, I think that is the multiple most buyers will offer. Popedope: I am also thinking of keeping it Lets allow it to get older by a few months and then sell for a bigger price..
You won't sell it for a bigger price unless you up the revenue. Age doesn't really affect sites with minimal traffic. It's all about longevity. If the customer thinks they can get their investment back in... say... 4 months, then they will happily buy it for that price. If ur going to keep it with the aim of selling it for more down the line, you will need to boost the revenue and / or traffic in order to be able to command a higher price. I've sold well over 100 sites on here and sitepoint so I know what these people are like