Bag of the Banker

 This bag is cylindrical, roughly 6 inches in diameter and 18 inches tall with a simple leather strap. Six lines resembling white marble columns run along the sides. 

The opening of the bag is attached to an extradimensional creature that has an affinity for appraising and accounting. You can ask it to make change for you if you ask it to. For example, if you give it 20sp, it will hand you 2gp. You can also give it gems, art pieces, or other forms of treasure and it will provide you with the equivalent value in gold.

Notes: Control, Utility, Combat, Container