If budget is a concern, consider free, open-source forum software like phpBB , Simple Machines Forum , or Discourse (has a free tier). These are secure, actively maintained, and legal.
Using a "nulled" version of vBulletin refers to using a pirated copy of the forum software that has had its licensing and verification checks removed . vbulletin nulled
While using vBulletin nulled might seem like an attractive option, it comes with significant risks: If budget is a concern, consider free, open-source
A common defense is: "I downloaded it from a reputable warez forum with good ratings." If budget is a concern