Poll: Gift of Hedone - Merchant "Loyal Customer"

Hello you wonderful deviants,

So for Vendors/Merchants as you know I want to do my best to make them "interactable" My original plan for the Mysterious Merchant was to have like a bartering system, where you would try to "successfully" barter. But I started to dislike that concept more and more. Now what I'm thinking of is more a "Loyal Customer" system where she "treats" her best customers. But how would you prefer she do that.

Option 1:
Like a stamp card where after your 10th Purchase she "treats" you

Option 2:
Spend a certain amount in one shop and she "treats" you, but it would increase each time as you would get more money.

Option 3:
Cumulative over the course of the game with different tiers you unlock, with each threshold you hit being another "treat"

I am also open to other suggestions! :)