Depends on what your free product or service is.
Start off by promoting on related websites, that offer link trades, or submit a site type search engines.
If the website is good enough, word of mouth will spread, and that is the best kind of advertising.
We are offering free webhosting.. small space.. but not giving an option to upgrade to paid..
they will have to upgrade to paid with some other web hosts and we ask when they do they come back to our site and vote and give experiences with the hosts they choose...
we are trying to push an unbiased webhosting rating site... so who would be willing to trade links? or banners?
I think web hosts would be to nervous to do this or send their customers to vote becuase they may be worried their customers may see someone else listed and decide to switch, but not thinking that the same can happen to them..
I am trying to keep this site totally free of anything paid so it remains a totally unbiased rating site...
Well, you can re-do your site’s design so that it’s slightly less confusing. Maybe it’s just me, but your homepage is a little wild I think.
I mean, your domain is “top25,” so maybe the homepage should display a list of the 25 most voted for sites. And you should have a comprehensive and detailed section allowing members to write reviews on those companies.
As for the advertisements, if you keep them on the top/bottom, and on the left/right navigational bars and just not right smack dab in the middle of the site, -> and then explain in your submit a site link that *no* payments are accepted for site ranking and what not -> I don’t think people will have misconception that it’s one of the countless “paid off” web hosting review sites.
It's just a few ideas... Ultimately, accepting funds for advertising would be a way to keep some money in your pocket while still offering a great service.