Shawn Collins of http://blog.affiliatetip.com answers a question from an affiliate about where to go to sell an affiliate website.
Q: I have built my affiliate marketing company up over the last 4 years but now what to sell it. I'd love to find a similar company that was recently sold to see what I could get for it. Is there a place where people are buying and selling affiliate businesses?
A: I haven't seen a community that is strictly about affiliate sites, but I would suggest checking out Flippa.
Flippa is a marketplace for buying and selling sites.
So, if you're in a niche that is somewhat popular, you should be able to see what similar sites are selling for.
Bear in mind that there are a lot of variables, such as the age of your domain, current traffic, and your revenue from the site.
Somebody else might have a similar site, but it could be five years older and making ten times more than your site, so obviously it wouldn't be worth the same as yours.
You could try eBay, too.