Pricing System

UnitPrice = StockItem.UnitPriceOverride >= 0
            ? StockItem.UnitPriceOverride
            : ItemData.ItemValue.BaseBuyValue.Value

Subtotal = UnitPrice * Quantity
Fee = ceil(Subtotal * (Config.MarketFeePercent / 100))
Total = Subtotal + Fee

Iron Sword:
  Base Price: 100 gold
  Merchant Override: 150 gold
  Quantity: 2
  Market Fee: 10%

Calculation:
  Unit Price = 150 (override)
  Subtotal = 150 * 2 = 300
  Fee = ceil(300 * 0.10) = 30
  Total = 330 gold

BaseValue = ItemData.ItemValue.BaseBuyValue.Value

BuyPercent = StockItem.BuyPriceOverridePercent >= 0
             ? StockItem.BuyPriceOverridePercent
             : Config.BuybackPercent

UnitBuyPrice = ceil(BaseValue * (BuyPercent / 100))
Total = UnitBuyPrice * Quantity

Iron Ore:
  Base Value: 50 gold
  Vendor Buyback: 30%
  Quantity: 10

Calculation:
  Unit Buy Price = ceil(50 * 0.30) = 15 gold
  Total = 15 * 10 = 150 gold

Config.bReplenishOnBuyback = true;  // Sold items restock merchant

StockItem.ReplenishMode = EReplenishMode::NeverReplenish;  // This item never restocks

bool ShouldReplenish(StockItem)
{
    switch (StockItem.ReplenishMode)
    {
        case AlwaysReplenish:
            return true;

        case NeverReplenish:
            return false;

        case UseVendorDefault:
        default:
            return Config.bReplenishOnBuyback;
    }
}

// On player sell:
if (ShouldReplenish && Config.bHasStock)
{
    StockItem.CurrentStock = min(
        StockItem.CurrentStock + QtySold,
        StockItem.MaxStock
    );
}

Config.bReplenishOnBuyback = true
// All items: ReplenishMode = UseVendorDefault

// Result: Players can sell items, other players can buy them

Config.bReplenishOnBuyback = false

// Iron Sword: ReplenishMode = NeverReplenish
// Health Potion: ReplenishMode = AlwaysReplenish

// Result:
// - Swords sold by players disappear (economic sink)
// - Potions sold by players get resold (convenience)

Config.bReplenishOnBuyback = false
Config.bHasBuyList = true
BuyList = [Scrap_Metal, Broken_Gear, Ore_Impure]

// All items: ReplenishMode = NeverReplenish

// Result: Acts as item sink for cleanup/economy balance