In the Krypt where you purchase extras for the game there are glowing green puddles on the ground in 4 locations which each have 5, 000 Koins equaling 20,000 Koins in total.
1. The first location is along the wall in the forest under a demon face statue.
2. The second location is along the wall on the opposite side of the Krypt in the Blood Marsh under another demon face.
3. The third location is on the right side of the Krypt entrance.
4. The fourth and final location is next to one of the obelisks in the cemetery.