Poes can be found all over the Depths, often in clusters or clumps along the ground. The small statue head can be found in her workshop, but will be dormant until you travel to the Depths yourself and find one of the glowing blue wisps known as Poes.
For most players, you can spot the first Bargainer Statue above ground, as part of Josha's excavation of The Depths in Lookout Landing.
