Trade system/Button

Hi everyone. I need your help. It is necessary to make a trading system between NPC
and players. To begin with, I made a system of reactions to buttons. Each button has a random reaction. It is necessary to make it so that if the reaction matches, it shows plus one to loyalty, and so on up to 4 choices. Therefore, the price becomes either lower, or yours after 4 clicks on the buttons. Screenshot in attachment. I really need your help