csharp
class EC_PlayerAccount : EDF_DbEntity
{
    private static const int DEFAULT_BALANCE = 1000;
    private static const int DEFAULT_CASH = 500;
    
    private int m_iBalance;
    private int m_iCash;
    
    EC_PlayerAccount EC_PlayerAccount() {};
    
    static EC_PlayerAccount Create()
    {
        EC_PlayerAccount instance = new EC_PlayerAccount();
        instance.m_iBalance = DEFAULT_BALANCE;
        instance.m_iCash = DEFAULT_CASH;
        return instance;
    }
    
    int GetBalance()    { return m_iBalance; }
    int GetCash()         { return m_iCash; }
    
    void AddBalance(int amount) { m_iBalance+=amount; }
    void AddCash(int amount)     { m_iCash+=amount; }
    
    bool RemoveBalance(int amount)
    {
        if (m_iBalance - amount < 0) return false;
        m_iBalance -= amount;
        return true;
    }
    
    bool RemoveCash(int amount)
    {
        if (m_iCash - amount < 0) return false;
        m_iCash -= amount;
        return true;
    }
}

csharp
[EPF_PersistentScriptedStateSettings(EC_MoneySystem), EDF_DbName("MoneySystem")]
class EC_MoneySystemSaveData : EPF_ScriptedStateSaveData
{
    ref map<string, ref EC_PlayerAccount> m_PlayerAccounts;
}; 

class EC_MoneySystem : GameSystem
{
    ref map<string, ref EC_PlayerAccount> m_PlayerAccounts = new map<string, ref EC_PlayerAccount>; 
    
    //---------------------------
    
    static EC_MoneySystem GetInstance()
    {
        if (!Replication.IsServer())
            return null;
            
        World world = GetGame().GetWorld();
        if (!world)
            return null;
            
        return EC_MoneySystem.Cast(world.FindSystem(EC_MoneySystem));
    }
    
    //---------------------------

    override void OnInit()
    {
        EDF_DataCallbackSingle<EPF_ScriptedStateSaveData>callback(this);
        EPF_PersistentScriptedStateProxy.CreateAsync(this);
        
        SCR_BaseGameMode gameMode = SCR_BaseGameMode.Cast(GetGame().GetGameMode());
        gameMode.GetOnPlayerSpawned().Insert(OnPlayerSpawned);
    }
    
    override void OnStopped()
    {
        EPF_PersistentScriptedStateProxy.Destory(this);
    }
    
    private void OnPlayerSpawned(int playerId, IEntity player)
    {
        string uid = EC_PlayerUtils.GetPlayerUID(player);
        if (!uid) return;
        
        if (!m_PlayerAccounts.Contains(uid)) m_PlayerAccounts.Insert(uid, EC_PlayerAccount.Create());
    }

    //---------------------------
    
    EC_PlayerAccount GetPlayerAccount(IEntity player)
    {
        int playerId = GetGame().GetPlayerManager().GetPlayerIdFromControlledEntity(player);
        string uid = GetGame().GetBackendApi().GetPlayerIdentityId(playerId );
        if (!uid || uid.IsEmpty()) return null;
        
        return m_PlayerAccounts.Get(uid);
    }
}

override EPF_EReadResult ReadFrom(notnull Managed scriptedState)
{
    EC_MoneySystem moneySystem = EC_MoneySystem.Cast( scriptedState );
    m_PlayerAccounts = moneySystem.m_PlayerAccounts;
    return true;
}
    
override EPF_EApplyResult ApplyTo(notnull Managed scriptedState)
{
    EC_MoneySystem moneySystem = EC_MoneySystem.Cast( scriptedState );
    moneySystem.m_PlayerAccounts = m_PlayerAccounts;
    return true;
}