Achievements - (Negotiable) (Shadow of the Tomb Raider)

Went through the whole game, collected all collected 96 out of 99 achievements, and one of them a bargain.
(From description says, buy from a dealer. In the first village the river will be a seller. Buy him anything.). Started a new game + reached Kuvak-Yak because before that no more merchants bought him and nothing has changed! Tell me who and where and how to take this achievement!