In the metal-free economy, the standard coin designations are used to refer to non-metallic methods of currency. These units share the same relationship and average costs as standard D&D currency.
CP: Cowry Pieces
Small, colorful shells traditionally formed into necklaces and bracelets, the tribes near oceans provide currency for the other tribes as one of their primary exports.
SP: Shell Pieces
Formed from fragments of opalescent shells of larger size than cowries, each tribe has a primary type of SP based on the common shelled animals in the area. Because of this, SP commerce is very common within a tribe, but inter-tribe commerce relies on the other forms of currency and trade goods due to an uncertain exchange rate.
GP: Glass Pieces
Traditionally, glass blowers produce large, colorful beads with any glass that is not used for other tools. These provide a standard amongst many tribes. Like SP, however, their value may vary across tribal regions. Many attempt to convert to gems for high-value, long-distance trade.
PP: Pearl Pieces
In general, pearls of a fairly standard size and quality are accepted at an average value. Pearls outside of this range may vary in their worth, being treated as gems, but a number of pearls are useful for high-value trades as a standardized currency.
Trade Goods, Gems, and Haggling
A substantial amount of the economy is based on barter, whether direct or through an intermediary merchant. Goods will typically be labeled with a range of potential prices based on their type, size, and quality. Characters can generally trade directly by exchanging the minimum value of their items for the maximum value of the purchased goods.
In order to receive a more equitable trade, characters must haggle. To haggle, each party establishes a beginning offer (based on the maximum and minimum value of the items traded).
Characters can make a Bluff check against a DC of the other party's Sense Motive + 10 to create a starting offer well above or below the standard values.
Each round of a haggling session, each party makes a Diplomacy check against a DC of the other party's Appraise + 10. If successful, the other party must make a new offer that is closer to the middle by roughly 10%. Since rounds occur simultaneously, both parties may move a step towards the middle if both are successful. Haggling stops when both parties reach the same value, or one decides to accept the other's current offer.
For example: Anoch is trying to sell a stack of leathers to Bursad. The leather is valued at anywhere between 8 and 20 SP. Anoch's initial proposal is 20 SP. Bursad successfully bluffs and states that he is not interested in paying more than 4 SP for the entire lot.
The first round, Anoch's Diplomacy check is successful and Bursad's is not. Bursad admits that he might go as high as 6 SP for the lot.
The second round, both checks are successful. Anoch suggests he can go as low as 18 SP, and Bursad counters with 8.
The third round, both are successful again. Anoch drops to 16 and Bursad admits he could pay 10.
The fourth round, Bursad fails his check while Anoch is successful, and the offer raises to 12. Since he is in a hurry, Anoch accepts 12 SP for his leathers, rather than continue haggling.
All weapons used by the cursed races are made of non-metal minerals and plants. Slashing weapons are made of knapped flint, obsidian, or plate glass, typically bound to a wooden shaft. Piercing weapons are typically made of bone or sharpened wood. Bludgeoning weapons are made of wood or stone.
All weapons are available in non-metallic forms. For example, swords may resemble obsidian saws with a wooden spine, but still use the same standard statistics.
All non-metallic weapons, including traditionally non-metallic ones such as staves and bows, break on a critical fumble until they are repaired by a weaponsmith with the proper tools. They are also weak to the sunder effect, having a much lower hardness and HP per inch than metal. However, other than these features they are not further penalized.
All metal weapons are treated as adamantine. Even the staves and bows of metal-users are typically reinforced with metal and gain these properties. They ignore hardness of less than 20 for sundering attacks. They are treated as enhancement +1 even when not enchanted. They have 1/3 more HP than listed and Hardness 20.
All armors used by the cursed races are non-metallic. Player characters only have access to the first three armor classes at character creation (padded, leather, and hide). Armors greater than +3 must be created from rare hides such as ankheg shells or dragonskin. These are rare enough that they are not commonly available, and must typically be found during play and given to a skilled armorsmith.
Wooden shields function normally.
All metal armors are treated as adamantine. Even the light armors of metal users are typically studded or ornamented with some metals and gain these properties. Light armors bestow damage reduction 1/- upon the wearer, medium armors grant 2/-, and heavy armors grant 3/-. Shields do not grant extra damage reduction. They also have 1 less armor check penalty, due to being considered masterwork. They have 1/3 more HP than listed and Hardness 20.
The cursed races do not imbue magic directly into weapons and armor, as even the best enchantments do not always protect an item from wear or destruction (enchanting does not make a non-metallic item harder unless purchased as a +1 value item property). The metal-users have trouble making the world's natural magic adhere to metals, so only directly enchant purely divine artifacts.
Instead, most enchantments are of gemstones specifically configured to bestow their magic on a properly prepared item. Cursed race items will traditionally be ornamented with thongs of feathers, bone, and enchanted gems. Metal users will often set their enchanted gems directly into the metal item.
In all cases, the gems from an enchanted item can be cut or pried loose, and retain their enchantment. With an hour-long ritual that costs no additional resources, a character with the requisite item creation feat to have originally created the enchantment can transfer it to a similar item by attaching the gems.
Other Gear and Tools/Technology Level
Most items on the PHB lists are available as long as they have a reasonable non-metallic analog. As noted in the trade goods section, many goods will have a variable value due to the barter culture.
In general, the technology level of the cursed races can be placed as similar to tribal cultures in the real world before Western arrival. Living structures are hide tents, wattle and daub huts, and caves as appropriate, with well-off individual living in wood and thatch cottages or adobe dwellings. Important military fortifications are made from concrete-mortared unfinished stone and fired bricks. Due to the brittleness of chopping and quarrying tools, few structures are built with unnecessary smoothness. However, many dwellings do feature elaborate painted or carved designs. Some of the greatest structures of the cursed races are built purely from magic.
Many technologies that do not require metal directly for their development are at medieval levels or better; the cursed races are quite ancient and have access to divinely-inspired wisdom and are simply limited by their tools, not by ignorance. Herbal and alchemical sciences are fully normal for D&D, and glassmaking is possible (though difficulty in setting means there are few lenses) if not useful for many structures. A wide variety of animals are domesticated, and some tribes specialize in taming burrowing beasts to increase their ability to mine. Shipmaking is still limited mostly to canoes and sailed rafts and barges; it is difficult to make reliable deep-water vessels without metal fasteners. Some deep-water ships do exist, however, largely due to magical production.
Knowledge is passed almost entirely through oral tradition. Most tribes have a library of important pictographic symbols, but these are used for warnings and markers, not for elaborate discourse and record keeping. An ancient phonetic alphabet is generally taught to most children, but it is little used. Spellbooks typically take the form of rings of carved bones or shells bearing intricate patterns that somehow remind the owner of how to cast the spell.