"Do I need to pay for Java"
tldr: only if you don't want to be hacked after Jan 2019
if you use some kind of oldschool Java webapp that uses Applets or JWS, ie, every corporation in existence and everyone who has to deal with a government, then almost certainly you will need to buy Oracle Java 8 patch support unless all the webapps YOU use have completely rewritten THEIR website front-end logic
or you could just let your Java 8 quietly turn into a virus magnet