“You are the heavyweight champion of Northern California. You have gained fame, respect, the love of thousands... and a bonus to your toughness and unarmed skill.”— Fallout 2 description
Prizefighter is a reputation title in Fallout 2.
You get this title by defeating the Masticator or Xander Holyland during the final boxing match at the Jungle Gym in New Reno.
The bartenders and drug dealers charge more because their Barter modifier is set up to charge more when they likely were meant to be less.