Install another language to forum, only pay ?

Hello I have created a forum here and change the language to have it in English, and I put it in Spanish. I go to the window language of the administration of the forum and I see:

  Languages    This section allows you to manage the lagnuages on your forum. You can get additional languages by going to the upgrades section to order a language pack
 I have to go to:
http://asdad.createaforum.com/upgrades.php

and pay:

Language Packs: $ 25.00
     Adds another language for use on your forum.
     One time fee // what this ? 1 pay forever

 

Thanks

Yes it is a one time fee forever.