These are the goods which exist in a game and which characters may purchase.
Goods are typically purchased through the use of currency - and though many kinds of currency exist, they are generally simplified into what they are made from. Platinum, gold, and silver are the common currencies of the era while electrum, copper, and bronze were typically used in much earlier time periods.
Within the game, most goods will be bough using Silver Pieces. The other denominations of currency are useful as well - but are not primarily needed.
These coins are used in the modern day, and are often referenced in the game when discussing prices. Platinum is usually only seen by nobility who wish to hold a great deal of currency on-hand at once. Gold is often held by merchants, or sometimes by regular townsfolk who have been saving up a good deal of money. Silver however is used by everyone and is often what people are paid with when working their jobs, and is the standard for the economy (hence most item costs being listed in Silver).
One Platinum Piece (PP) is equivalent to 100 Gold (or 5,000 EP, 10,000 Silver, 500,000 CP, or 5,000,000 BP)
One Gold Piece (GP) is equivalent to 100 Silver (or 0.01 PP, 50 EP, 2,500 CP, or 25,000 BP)
One Silver Piece (SP) is equivalent to a pair of clothes or simple meal for the day. (50 CP or 250 BP)
Ancient currencies used in old societies, and are usually found in large amounts in old treasure stashes. Electrum is the only one of the three currencies with much value anymore, and is made of a combination of silver and gold. It used to serve a similar purpose to Platinum, however it wasn't nearly as rare as Platinum is now. Copper and Bronze serve a similar function to Silver today, being used by citizens often and people are usually paid in a combination of both currencies (often denoted as 5 C/ 2 B in ancient letters).
One Electrum Piece (EP) is equivalent to 100 Copper (2 SP, 100 CP, or 500 BP)
One Copper Piece (CP) is equivalent to 5 Bronze.
One Bronze Piece (BP) is equivalent to a simple meal back in the ancient times.
Equipment is typically sold to merchants in villages and cities, or bartered to trade equally valuable goods with others. Often the skill Haggling is used during business transactions, and merchants almost always possess it alongside Appraise. This aspect of trade also determines the kind of stock the merchants of a village carries, and often these merchants don't carry exorbitantly valuable goods such as magical items or illegal goods (such as valuables which once belonged to nobility).
When selling, typically you will get half the listed price without attempting to haggle and assuming the merchant isn't attempting to swindle you. Haggle can be used to get more from the target, and when making checks use half of the listed price as the base and then increase it by the result of the check.
When bartering you use half the listed price as the item's Barter Value (BV) in order to determine how much you can get through bartering with the item. Some items are worth less to certain merchants (such as bartering with a jewelry merchant and giving him a bundle of longswords) and as such, some merchants may value the item at less than half its listed price (however this never goes below 30% of the listed price).
Attempting to barter 10 of the same item decrease their overall value by 5% due to bartering in bulk, 30 decreases overall value by 10%, 60 decreases overall value by 15%, and 90+ decreases overall value by 30% which is the maximum reduction which can be applied for bartering in bulk. You may ignore these rules for bulk goods when selling the items normally, or when bartering the item with an appropriate seller (for example, bartering weapons with a blacksmith, or jewelry with a jeweler, as opposed to vice versa). A successful Haggling check (DC = 20 + total reduction percentage, max DC 50) negates the reduction percentage altogether.
All items possess Integrity Points, a pseudo Hit Point pool which items use to determine whether or not they're broken or destroyed. When dealing damage to items, some damage types deal more or less damage to different kinds of materials (such as fire dealing more damage to webs or paper).
Magical objects are tougher than nonmagical ones, usually being able to destroy nonmagical objects with an easier time and are more resistant to breaking from nonmagical means. Magical objects take half damage from nonmagical damage sources (excluding nonmagical elemental damage) and nonmagical objects take double damage from magical weapons attempting to Sunder.
Items which possess Defense Points such as armor, count their Integrity as 1 + Defense Points for Head armor, 25 + Defense Points for Body Armor, and 8 + Defense Points for Arm and Leg armor, and finally 10 + Defense Points for Shields. Armor which doesn't possess any more Defense Points is instead considered broken through, and further damage isn't applied to Integrity unless the opponent deliberately attempts to break the armor (such as through Sundering).
Elemental damage types damage objects normally unless otherwise specified, and objects take no damage from psychokinetic damage, smiting damage, or damnation damage.
Materials often determine the Integrity Points of objects, walls, and other forms of equipment. The exception is armor and weapons which already have their Integrity Points determined. Weapons and armor have their own pages for special materials which would determine their bonuses or penalties to Integrity Points. Walls typically have 1 foot of thickness for the purpose of calculations, doors possess 1 - 3 inches of thickness, and furniture usually has 1 - 4 inches of thickness (depending on the furniture's size).
Paper, Rope, and Cloth are weaker and typically only possess 2 points of Integrity per inch of thickness and take double damage from sources which deal fire or slashing damage.
Glass is often used in houses and homes to function as windows. They typically possess 2 points of Integrity per inch of thickness and take double damage from sources which deal sonic damage.
Ice is usually only found in large amounts in natural environments. They typically possess 3 points of Integrity per inch of thickness and take no damage from water or ice damage, and take double damage from bludgeoning and fire damage.
Leather and Hide are usually found in animal hide armor or in furniture. They typically possess 8 points of Integrity per inch of thickness.
Wood is found almost everywhere but most commonly it is used to build houses. They typically possess 15 points of Integrity per inch of thickness, and takes double damage from sources which deal fire damage.
Stone is found often in houses (especially among the Dwarves) and is commonly used for roads as well. They typically possess 24 points of Integrity per inch of thickness and take double damage from sources which deal earth damage, but half damage from piercing or slashing damage.
Iron and Steel are typically used in fashioning weapons, objects, chests, and some smaller furniture. They typically possess 40 points of Integrity per inch of thickness and take half damage from piercing damage.