title: do all packages in nuget have free licence to use?
body: <p>I am working on a project which require manipulating Excel files. I found a library for this job called Aspose.cells. it is not a free library and we should buy its licence from its site in order to use it in our projects. However, I found that there is a nuget package of this library. So I am a bit confused and wanted to ask these questions:</p>
  
  <ol>
  <li><p>Since I met nuget I have been thinking that all packages exit on
  it are free though this one seems to not be. Any description?? </p></li>
  <li><p>I remember one of my friends used Aspose.cells without buying any
      license what would happen if I did so?</p></li>
  </ol>