Items
Source GM Core pg. 48
After an adventure yields a windfall, the characters might have a number of items they want to sell. Likewise, when they're flush with currency, they might want to stock up on gear. It usually takes 1 hour of downtime to sell off a few goods or shop around to buy a couple items. It can take longer to sell off a large number of goods, expensive items, illegal goods, or items that aren't in high demand.
An item can usually be purchased at its full Price and sold for half its Price. Supply and demand can affect these numbers, but only occasionally. However, the game leaves it up to you to determine what items the PCs can and can't purchase and the final market Price for them. Settlements the size of a town or bigger typically have at least one vendor for basic, common gear, and even magic and pharmaceutical items of 1st level. Beyond that, it all depends on how much you want to allow the players to determine their abilities and how much verisimilitude you want in your game. If the settlement has access to a planetwide infosphere, it's usually possible for your PCs to find what they need that way, even if it takes 1-2 days for their item to be delivered via courier or drone. You can set the specifics where you need, but let's look at three possibilities.
PCs can buy what they want where they want. You gloss over the details of markets. PCs can sell whatever they want for half the Price and buy any item to which they have access at full Price. This approach is focused on expediency over verisimilitude and is likely to reduce the number of unusual or distinctive items the PCs have, as many players seek out the ones that most directly support their characters' strengths. This still means there's a limit on purchasing uncommon or rarer items, but you could even do away with rarity if your group wants, or add a surcharge instead (depending on your group's play style, that could be anywhere from 10% to 100% for uncommon items, and 25% to 500% if you also want to open up all rare items).
PCs can buy what they want but must put in additional effort. If they want to sell or buy items, PCs must be in a location where the markets can support that. They can usually sell a single item for half its Price, but the Price for selling something already plentiful on the market could be as low as 25% (or they can ship it to a buyer in another market, if they can find one, making 40% of the item's Price after paying for shipping). Buying an item usually costs the full Price; buying higher-level items (or uncommon items if they're available at all) requires seeking out a special vendor or NPC and can take extra time, representing getting the item shipped to the PCs. They might be unable to find the item at all even after their time investment, based on the settlement's parameters. This approach allows PCs to determine some of their items, but it forces them to really work to get more powerful items and discourages looting every enemy to sell off fairly ordinary armor. This can be the most work for you but can make the world feel diverse and complex.
High-end markets are rare or nonexistent. PCs get what they find in adventures and can Craft their own items, if you allow them to get formulas in some way. If you have high-end marketplaces at all, their selections are small. They sell items at full Price and have difficulty attaining the funds to buy more items. They might purchase items for half of the Price but are far more selective about what they take. If you use this approach, PCs are far more likely to use strange items they find but might be dissatisfied or even underpowered depending on what items you give them. Even in this style of game, you might want to allow them to get upgraded weapons and armor fairly easily, or make sure you award those on a regular basis.
Universal Polymer Base Conversion: You can reduce the amount of time it takes for PCs to sell items by allowing PCs to reduce the items to UPBs. These services can be found at most major settlements and allows the conversion of any tech gear into its base components, resulting in 50% of the equipment's value in UPBs. You might lower the redeemed value up to 10% to represent the cost of using the facilities or the material lost in the process. Magitech and magic gear will only give up to 25% of the item's value, as most of the cost of those items is in the magic that's lost in the process of converting the items to UPBs.
An item can usually be purchased at its full Price and sold for half its Price. Supply and demand can affect these numbers, but only occasionally. However, the game leaves it up to you to determine what items the PCs can and can't purchase and the final market Price for them. Settlements the size of a town or bigger typically have at least one vendor for basic, common gear, and even magic and pharmaceutical items of 1st level. Beyond that, it all depends on how much you want to allow the players to determine their abilities and how much verisimilitude you want in your game. If the settlement has access to a planetwide infosphere, it's usually possible for your PCs to find what they need that way, even if it takes 1-2 days for their item to be delivered via courier or drone. You can set the specifics where you need, but let's look at three possibilities.
PCs can buy what they want where they want. You gloss over the details of markets. PCs can sell whatever they want for half the Price and buy any item to which they have access at full Price. This approach is focused on expediency over verisimilitude and is likely to reduce the number of unusual or distinctive items the PCs have, as many players seek out the ones that most directly support their characters' strengths. This still means there's a limit on purchasing uncommon or rarer items, but you could even do away with rarity if your group wants, or add a surcharge instead (depending on your group's play style, that could be anywhere from 10% to 100% for uncommon items, and 25% to 500% if you also want to open up all rare items).
PCs can buy what they want but must put in additional effort. If they want to sell or buy items, PCs must be in a location where the markets can support that. They can usually sell a single item for half its Price, but the Price for selling something already plentiful on the market could be as low as 25% (or they can ship it to a buyer in another market, if they can find one, making 40% of the item's Price after paying for shipping). Buying an item usually costs the full Price; buying higher-level items (or uncommon items if they're available at all) requires seeking out a special vendor or NPC and can take extra time, representing getting the item shipped to the PCs. They might be unable to find the item at all even after their time investment, based on the settlement's parameters. This approach allows PCs to determine some of their items, but it forces them to really work to get more powerful items and discourages looting every enemy to sell off fairly ordinary armor. This can be the most work for you but can make the world feel diverse and complex.
High-end markets are rare or nonexistent. PCs get what they find in adventures and can Craft their own items, if you allow them to get formulas in some way. If you have high-end marketplaces at all, their selections are small. They sell items at full Price and have difficulty attaining the funds to buy more items. They might purchase items for half of the Price but are far more selective about what they take. If you use this approach, PCs are far more likely to use strange items they find but might be dissatisfied or even underpowered depending on what items you give them. Even in this style of game, you might want to allow them to get upgraded weapons and armor fairly easily, or make sure you award those on a regular basis.
Universal Polymer Base Conversion: You can reduce the amount of time it takes for PCs to sell items by allowing PCs to reduce the items to UPBs. These services can be found at most major settlements and allows the conversion of any tech gear into its base components, resulting in 50% of the equipment's value in UPBs. You might lower the redeemed value up to 10% to represent the cost of using the facilities or the material lost in the process. Magitech and magic gear will only give up to 25% of the item's value, as most of the cost of those items is in the magic that's lost in the process of converting the items to UPBs.