Money is the standard currency of the game and is used to purchase items from playershops, adminshops, the Auction House, and to pay people with the /pay command. Doing /bal or /balance will tell you how much Money you have on your person. 5% of that Money is lost upon death. Money can be stored in a Guild Bank or in the form of items that can be sold to the Market Vendors.
The Market can be accessed using the command /warp market, or by going through the portal at the end of the path where the Spawn Vendors are. Its main purpose is to buy items from you for Money, but there are a few items you can buy there in the Treasure Trove.
The Wild is a PvP zone where keepinv is off, but contains multiple chests that have around ~1-2K Money in them each. Only one player can loot a Wild chest at a time and contents are refreshed a few hours after looting.
Most dungeons have some form of reward that either is cash or can be turned into cash at The Market or by Trading.
You can use Playershops and the Auction House to sell (as well as buy) items for Money.
You can create a Playershop by left clicking a chest that doesn't already have a Playershop with an item you want to sell/buy. If you are selling items, you need to stock the chest with the item listed in sign for other players to be able to buy from it. If you are buying an item, after you create your Playershop, right click the sign and a prompt in your chat should show up in your chat window to modify your shop settings, go to the line that says "Shop Mode: Selling [Change]" if you click on the [Change] it will change the status from selling to buying and from buying to selling.
There are two different Auction systems in the server, one being the Auction NPC at Spawn, and the other being the Auction House accessed by /ah. Most players use /ah. You sell items in /ah by using the command /ah sell [Amount of Money you want to sell it for]. To buy an item, you click on it as long as it's not from the bottom row, an item for sale will list its seller, price, and how much time is left for it to be up in the auction house. It will ask you to confirm your purchase and clicking the green glass pane will confirm the purchase. Clicking the red pane will exit you out of the purchase. You can take down a /ah listing of yours by clicking on the bottom left item that should say something like "My Listings" and it will take you to a page with your listings, click on the item you want taken down and it will be sent back into your inventory.