use strict;
use warnings;

my @listOfPass;
my ($section,%passwds);
while(<DATA>) {
    chomp;
    if (/^\[(.*?)\]$/) {
        $section = $1;
        next;
    } elsif ($section eq 'PASSWORDS') {
        my ($mkt,$pass) = split;
        push @listOfPass, $pass;
    }
}#end while loop

print join(',', @listOfPass);


__DATA__
[PASSWORDS]
GUY    ddd
GIRL   dfd33
BOY    df341
[download]

UPDATE I just reread the OP. The passwords need to be in the order that they were received. I modified this code to use the push function like Ovid suggested. I got too trigger happy with my caffeine induced post :)