my @items = (
    # 0
    [  'sword', 'mace', 'turtle' ],
    # 1
    [ '+1 sword', '+1 mace', '+1 turtle' ],
    # 2
    [ 'frost sword', 'frost mace', 'frost turtle',
      'flame sword', 'flame mace', 'flame turtle' ],

    ...
); 

##</code><code>##

my @in_range = map @{$items[$_]}, 3..5;
my $item = $in_range[ int rand( @in_range ) ];