For this achievement you'll need to search through 200 containers in the game. That being said you'll need to loot from desks, boxes, trash bins, chests, and any other containments. Now this achievement should be a work-in-progress as you'll be on the lookout for health/salts, ammo, money, and other valuables along the way.
Once you've managed looting 200 containers you'll pop this 10G achievement!