You can get a random subset without replacement using List::Util::shuffle().

use List::Util qw/shuffle/;
sub pick {
    return if @_ != 2;
    my ($num, $count) = @_;
    (shuffle 1 .. $num)[0 .. $count-1];
}
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To build a sample of picks with repetition allowed:

my ($top, $ct, @samples) = (158, 8);
my $size = 50,000;

$#samples = $size;
$_ = [pick( $top, $ct)] for @samples;
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You can keep them unique by storing the samples as keys of a hash,

my %sample;
$sample{join ',', pick($top, $ct)} = undef
    while $size > keys %sample;
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If you need a memory-breaking large sample, look to a file or database to hold it. Tie::File would be simple to use for that.

Does order matter in a sample? If not, then sort them to get a canonical order before storage.