From the FAQ:
Can I use Nolics.net 2005 as part of my Sitefinity Community Edition License?
Nolics is integrated in the Sitefinity build and it’s used in runtime by Sitefinity (in both Sitefinity Community and Standard Edition). With the Sitefinity Community Edition you will be able to use Nolics.net 2005 only in runtime whereas the Standard Edition also allows you to use the product in design time in Visual Studio
What does runtime versus design time mean exactly?
I am using the Community Edition. Can I use Nolics to extend Sitefinity? I created a "dbclass" file with Notepad and placed it in the "App_Code" folder. It doesn't seem to do anything though. Would I need to purchase Nolics or Sitefinity for this to work?
As an aside, I'm not at all opposed to buying software, but I'm learning Sitefinity on a personal project. If it proves to be as great as I hope it will be I will use it on future client projects; right now I'm just evaluating though.