[Mean]

pawn Код:

new level[playerid];

Somewhere you put

pawn Код:

level[playerid] = 1; // replace 1 with the level you want

And detecting if player is desired level:

pawn Код:

if(level[playerid] < 1) // change 1 to the level you want command to be usable at
    return SendClientMessage(playerid, 0xAAAAAA, "You need to be level 1+ to use this command");