In the Post-Apocalyptic wasteland old dollars and paper money has lost all its value, in the present people use bottlecaps as the main coin. Bottlecaps, also simply known as caps, are sturdy, easy to find and hard to falsify, this reasons made them perfect for the inhospitable wasteland.
The country of 'Ohana attempted to forge their own money and ended smelting several iron coins which they called Kames; this worked for a few years while the 'Ohanan economy was stable and steady but after the many invasions and disasters that the country suffered the coin was completely devalued and people returned to Bottlecaps. Nowadays Kame coins are nothing but a cheap souvenir or a collector's item.
To earn Bottlecaps you have to create threads and write in subforums that include the Hawaiian Wasteland and its many islands and settlements. For each message or thread that you write you will earn a small quantity of caps. This is to represent the money and small valuables that your character finds on their journey, be it by looting corpses or in containers. The money earned this way isn't going to be much, just enough to barely survive.
After the end of each quest you will also receive a reward composed of both caps and items. The better you roleplay the bigger will be your reward.
If for any reason you end with a negative amount of caps several repo men and bounty hunters will come to you. If you cannot afford to pay your debts you might end enslaved or killed.
To expend your money you have to travel towards an area where one can buy and sell. In that place there will be an open thread to buy and sell items. You have to decide what to buy and a Moderator will answer with how much it will cost you, this price will vary depending on several factors, like your reputation and your barter skill. You can attempt to bargain for a better price and your success on it will depend on a dice roll, albeit if you get a really low dice roll you might end offending the seller and become unable to buy anymore. After deciding for a price the Moderator will remove the needed money and add the item to your character's inventory.