Before it was abandoned, Auditor was a broker addon that not only remembered the gold balance of each character, but in the chat window it displayed how much gold you spent at any vendor that accepted gold (including the AH) after you closed the window.
It was nice to have that kind instant feedback when I went on shopping sprees for ore [grumble-grumble] jewel crafting [grumble-grumble]. It’s a QoL feature that I miss every time I visit a vendor of some type.
Can anyone recommend currency addons that have that feature?