Most free online press release posting sites have gone the way of the rotary phone. Google used to look favorably on links in press releases for SEO purposes, but that’s no longer the case, so there are few left to choose from. The best way to find one is to search Google for “free SEO press release distribution 2016.”
Then, to make sure the site’s releases are picked up by Google News, search for the site at https://www.news.google.com. Let’s pretend our distribution site is called FreelancePR.com. In the Google News search bar, you would type the following, without the brackets: [site:freelancepr.com] (yes, there’s no space after the colon) and look for anything that seems to be a press release. Make sure to narrow your search results down to items posted in the previous week (because free press release sites are often de-indexed.)
If nothing from the site shows up in Google News, it’s probably not worth trying. It’s not there because Google doesn’t consider it to be an authoritative source of content.