my $full_time_devs = 20; # Guess
my $annual_work_hours = 1800; # Guess
my $hourly_us = 40; # *Total* guess
my $years = 2;

printf("\$%s\n",
       commify( $full_time_devs *
                $hourly_us *
                $annual_work_hours *
                $years
                )
      );

sub commify {
    my $text = reverse $_[0];
    $text =~ s/(\d\d\d)(?=\d)(?!\d*\.)/$1,/g;
    return scalar reverse $text;
}
__END__
$2,880,000