Generous

Generous is a secret achievement in Metro 2033, and a regular achievement/secret trophy in Metro 2033 Redux.

Overview
This achievement is awarded for being generous to Metro dwellers and donating bullets when asked. You need to give a bullet to three different people: a boy, a man and a vagrant:
 * The man and his wife, in the Exhibition marketplace, need two bullets to pay for medicine for their son.
 * A boy will escort you to Bourbon on the Black Street in return for a bullet, in Riga.
 * There is a vagrant near to where the boy was, sitting on some stairs, who asks for a bullet.