So 22 Cha with the hat from Rolan in Act 3, all speech skills expertise with tadpoles, and +1 persuasion / deception ring and it says -100% discount but stuff still costs money

I never bothered with the attitude thing because I heard it resets too fast.
Between 20 and 22 CHA, or taking the ring on and off, the prices did change but not a lot.
If you don't use a CHA main, Just use Wyll and take the persuasion expertise from his pact upgrades.
Or is it only proficiency with pact stuff, which wouldn't work because Wyll already has that:
https://baldursgate3.wiki.fextralife.com/Beguiling+InfluenceSo persuasion expertise is only for rogues or tadpole power?
Yea its only with illithid power
https://baldursgate3.wiki.fextralife.com/Illithid+ExpertiseActor feat is also only proficiency. The illithid power counts as both proficiency and expertise, nice to have on a char with 20-22 CHA and the +1 speech skills ring.
Welp, feed Wyll some tadpoles.