2intrigue,
I use press releases quite often for many different niches. They are essential going to do 2 things for you. #1. If its really news it might get picked up by news sources and then it gets around the net rather nicely- if its not news but still a press release worthy its still going to gather a little bit of notice. #2. Press release sites sometimes have some good back links coming in so they rank well with search engines like google. This also means that you may be included into google news etc. I believe to get listed in google news you must list you phone number and country.
This also means extra traffic for you as many times if you target your keywords right in your press releases that you can also land a top spot in google.
So I think that press releases are worth the time. As far as FREE or PAID i use both, it just depends on how big I think the news or announcement is and typically how much money can I make off of it in the long run.
Its also depends on if I want to deal with ads being on my PR's as free press releases usually have ads in them.
In my sig I have a traffic tips sign up. its free I go over press releases in much more detail in there.