Good news! You can carry a lot more money than you thought. Gold coins were really only officially and widely circulated in the Byzantine Empire. The coin was a Solidus, based on the Roman coin used only to pay soldiers, the Soldat. They both weighed 4.5 grams and were a bit smaller than a US dime. One hundred Solidus weighs one pound. For game purposes all of the coins weigh about the same, this would actually make them quite large compared to the gold, but we will hand wave that and make them of proximate size. I can hold about 90 dimes in one very full hand, so an average handful of AD&D coins is about 100. A small pouch would hold up to 500 coins, and a ton of gold would be worth 200,000 gold pieces. Our silver coins would resemble a French Denier, which was a silver penny, but we will call it a Shilling, traditionally worth 12 Pence, but we will treat it as 1/10 of a gold piece. The copper coins, which we call pennies or pence are worth 1/100 of a gold piece. Confused, good.
