https://www.gamewatcher.com/news/pathfinder-kingmaker-companions https://www.rpgsite.net/feature/7833-pathfinder-kingmaker-companions-guide-all-the-companions-and-where-to-find-them

Mercenaries

The cost of mercenaries increases with the level of your main character. You can reduce the cost significantly by delaying leeling up your character until after you meet Anoriel Eight Eyes at Oleg's Trading Post. The cost at level one says 500 gold but it's 100 gold.