[Faisal_khan]

Create a variable and use it something like this:

pawn Код:

new BegineerBonusRecieved[MAX_PLAYERS];

COMMAND:startbonus(playerid,params[])
{
    if(BegineerBonusRecieved[playerid] == 0)
    {
        GivePlayerMoneyEx(playerid,35000);
        SendClientMessage(playerid,COLOR_BLUE,"Du hast den Startbonus erhalten.");
        BegineerBonusRecieved[playerid] = 1;
    }
    else
    {
        //give the nxt bonus;
        BegineerBonusRecieved[playerid] = 0;
    }
    return 1;
}

Or you can also add it with your saving system.