Our currencies are based on the natural spawn rate of ores, their resulting mining, and refinement occurrences and pinned against the 'Standard Coal' set at $10 (See The Eco-mine-ist for references)

Every player has a bank account!  You can access your account balance, deposit currencies, and with draw currencies with the following commands as long as you are in the Homeworld Bank (or near an ATM):

/money [for account balance]

/withdraw (currency**) (amount) 
**Note that currency should be typed as: coal, redstone, iron, quartz, lapis, gold, diamond.

**Only deposited materials may be withdrawn - if a material cannot be withdrawn the bank is out and it must be mined.

In the server's spawn town, there is a marketplace where items can be bought and sold.  The market resembles a farmers market and the marketplace interface is located under an orange tent.  The marketplace interface is a stone button next to a designating sign.  Further 'how-to' instructions reside on signs to the right of the activating button.