This is basically a grand exchange system, but only on the forums. Here's how you use it, you can only sell prices from a range of prices, it CANNOT be set on a single price.
Example:
Selling Rune Scim 20,000GP=WRONG
Example2:
Selling Rune Scim 15,000-25,000 GP=CORRECT
To use the price range, you must use the pricelist located here:
http://sg-forum.info/showthread.php?t=264
Fortunately enough, Ancient Boom had added a price range in the pricelist, so you can just use that. YOU CANNOT GO BEYOND THE PRICE RANGE
A seller of an item will make a post on here saying what item they wish to sell and the price using this application-
Username Ingame:
Item Selling:
Price Range: #GP-#GP
If you are here to buy an item, you will use this application:
Username Ingame:
Item Buying:
Price you are buying for:
Also, if there are at least 3 of the items in the grand exchange list, the item has the option in being sold for 5% of the actual price less. If your item is one of the only 3 items currently being sold, it can be sold for 10% MORE than the price it already is.
The price ranges will be based on the Price List, located here:
http://sg-forum.info/showthread.php?t=264
Items Currently Being Sold-
CURRENTLY NOTHING IN STOCK
-
Latest update to the Grand Exchange: Added more info to price range