Microsoft announced today they will be giving everyone who has windows 7 or windows 8 a free upgrade to the new windows 10 when it is released later this year.
the free upgrade offer is only good if you do it within the first year so after that you will have to buy it if you wait too late and decide you want to upgrade then.
here is the article:
http://www.businessinsider.com/windo...ve-blog-2015-1