The Price Checker (also spelled price-checker) interface was introduced on 25 February 2009 to allow players to check the prices of items. This feature was one of the player-requested features added by Jagex in 2009, due to an overwhelming amount of "Price Check" spamming in-game, which was extremely annoying to the other players; see History for more information on this.
The interface is located within the Money pouch interface, upon performing a right click, and then left clicking Price checker. The price checker consists of small window in which an item from the inventory can be added or removed, while actively displaying the total and individual current Grand Exchange market price or high alchemy price of each item(s). The prices of up to 28 different items can be checked in this interface. If a player clicks an untradeable item or attempts to price check a members item on a free to play world, text then appears, stating: "That item isn't tradeable". If a player clicks the price checker while having another interface open, a text appears saying: "Please finish what you're doing before opening the price checker."
If the value of items displayed in the Price Checker window exceeds a certain value (2^31-1) then all that will be displayed is '----'. This is due to the fact that RuneScape uses a 32-bit integer to display the value.
At the bottom of the interface, the total value of all of the items is shown at the bottom on the centre. A button was added on 17 December 2013 to quickly add all inventory items to the price checker.
Before the Price Checker was introduced, players used an informal way of checking prices, typically referred to as "price check". To initiate a "price check", a player trades another player to see the Grand Exchange market price of his/her items; this method was used to ascertain the current worth of items in a convenient way, rather than looking each up, individually, via the Grand Exchange.
To start a price check, most players would repeatedly spam "Pc", commonly at a bank or the Grand Exchange, but players would also spam it at other places and wait for someone to trade with the player. When offered a trade, the player will put his/her items into the trade window; by doing this, the player may check the market value of items at the bottom of the trade window. After this price checking method is complete, the trade is declined, often annoying players, and therefore, became a common topic on the Official RuneScape forums.
With the addition of the Money pouch on 6 December 2011, there is a right-click option to bring up the Price Checker on the Money pouch, giving you two ways to access the Price Checker. Then, later on 16 January 2012, in a hidden update, the original location of the Price Checker, in the Worn equipment tab, was removed.