Hello everyone.

could anyone explain me how to do the following:

like when i talk to a NPC like wise old man than he says hello sir would you like to buy member?

than i get a option to choose yes or no.

if i choose yes he takes 100m out of my inventory and says you are now a member! and than it change in the playersusername.txt file the member = 0 to member = 1 and i dc when i log back in i am member
if you know please tell me