Use a hash to eliminate duplicates. I have written a demo below to show how this can be done. There are other ways too of course.

use strict;
use warnings;
use Data::Dumper;

<DATA>;

my @products = keys %{{ map { /^\d+\s+(\w+)$/ ? ($1,1) : () } <DATA> }
+};

print Dumper(\@products);


__DATA__
price     product
200       shoe
20        shirt
10        shirt
5         hat
[download]

And the output:

$VAR1 = [
          'hat',
          'shirt',
          'shoe'
        ];
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