#!/usr/bin/env perl

use strict;
use warnings;

my $VAR1 = {
    '153-1' => {
        '19-4' => {
            'cost' => '6300.00', 'cost2' => '630.00'
        },
        '135-1' => {
            '68-4' => {
                'cost' => '300.00', 'cost2' => '130.00'
            }
        },
        '1069-9' => {
        },
        '35-1' => {
            '28-4' => {
                'cost' => '30.00', 'cost2' => '10.00'
            }
        },
    }
};

my $total = 0;
get_total_cost($VAR1, \$total);
printf "Total = %.2f\n", $total;

sub get_total_cost {
    my ($hash_data, $sub_total) = @_;

    for my $key (keys %$hash_data) {
        if (ref $hash_data->{$key} eq 'HASH') {
            next unless keys %{$hash_data->{$key}};
            get_total_cost($hash_data->{$key}, $sub_total);
        }
        else {
            if ($key eq 'cost') {
                $$sub_total += $hash_data->{cost};
            }
        }
    }

    return;
}