Are plugins lifetime or till subscription ?


I am a new member here and was eluded with the attractive plugins and community here and wish to e a part of the community and gain as much knowledge and help from here as possible.

Starting out, I am a bit confused, are the plugins I install from here for lifetime or only for the current subscription month only ?

Also, where can I discuss or post to take advice or suggestions on something I want to do in my site but dont know what plugin can do it or a particular theme I wish to know of that has xx xx features.

Will appreciate if someone can clear my doubts