It is better to use GetMaxPlayers(); Because if you have 20(for example) defined players from server.cfg then there is no need to go till 500(MAX_PLAYERS equals to 500).
pawn Код:
for(new i=0; i<GetMaxPlayers(); i++;)
{
if(IsPlayerConnected(playerid))
{
//Rest of the payday
}
}
here if(IsPlayerConnected(playerid)) or if(IsPlayerConnected(i))

??