Hello Sembj. I don't think there is a hard and fast rule as to breaking even. It all depends on luck, if you hit a hot topic, good research; you study your market and write what both advertisers and readers/ the advertisers customers want.
For visitors I have seen figures of one to two percent of visitors going to advertisements on any site, of these one or two percent only about ten percent may make purchases from an affilliate site such as Amazon.com. So you definitely need lots of views to bring up initial income levels above your web page being a business and not just a paying hobby.
You need not worry too much about unique visitors to your site. Return visitors are more important especially if they link your site or "Like" it on Facebook or Tweet about it. Your website should be a home base when you post here or on other sites link back to your site and make links to your posts here, setting up an RSS feed from your profile here to your website will update that site at the same time as you post here,., that link building will get you visitors as they follow your paper trail back and forth around the web.
Hope this helps, all the best.