While the subject of PnP is all the rage. Does anyone remember an explanation for the ability to carry around large amounts of gold?

Banks.

Or a "purse of holding", depends on the DM and the setting.

I think as it is than computer game they ingore thing like this as it doesnot add
to the fun. In the real world before they have coins they have barter tokens. Let
say I as than farmer need an new bronze plow, some basic supplies and my wife need
some new clothes, I want to be able to do bartering with 40 bushel of weat. 40 bushel of weat weight 2000 pounds. Than offical of the temple or city state vist my
farm to see how much weat I have than issue barter token of weats buskel like bake
clay thing that look like buskel of weats to use in bartering. The same principal apply to subway token in NYC.

Like to your character have to worry about carrying foods and water when their travel overland in this game. Sorry I got alittle OT.