Need sale price guidance

I would like to ask what you think the following would sell for:

I have a website that is ranked #1 on google for a mid to high level keyword concerning a soon to be release new product and I also have a handfull of other domains are related to the product, the site currently generates about $175 a month but once the commercials start the site will skyrocket. This site has extremely high potential to become a community site concerning this product as all other versions of the product have community sites that have thousands of members. It is very hard to have a trully unique site online but this one is close and I have been unable to find a site that is dedicated to just this product. Sorry for being vague but I am not going to release the domain at this time.

Any ideas on what this may be worth please post or pm me. Thanks for your help!.