[Konstantinos]

I'd use it like that:

pawn Код:

// global variable:
new
    bool: RandomPickup_HealthArmour[ MAX_PLAYERS char ], // false = health and true = armour (saving space)
    RandomPickup
;

// When a player dies (get the position and set the as the coordinates of the pickup):
new
    r_health_armour = random( 2 )
;
if( !r_health_armour )
{
    RandomPickup_HealthArmour{ playerid } = false; // Health
    // Create health pickupid:
    RandomPickup = CreatePickup( ... ); // EDIT THE LINE
}
else
{
    RandomPickup_HealthArmour{ playerid } = true; // Armour
    // Create armour pickupid:
    RandomPickup = CreatePickup( ... ); // EDIT THE LINE
}

// When a player pickups the pickup:
if( pickupid == RandomPickup )
{
    new
        Float: amount
    ;
    if( !RandomPickup_HealthArmour{ playerid } ) // health pickupid
    {
        GetPlayerHealth( playerid, amount );
        SetPlayerHealth( playerid, amount + RandomEx( 5, 30 ) );
    }
    else
    {
        GetPlayerArmour( playerid, amount );
        SetPlayerArmour( playerid, amount + RandomEx( 5, 30 ) );
    }
    DestroyPickup( RandomPickup );
}

// the random function for 5-30 percent
stock RandomEx( min, max ) //By ******
{
    return random( max - min ) + min;
}