use strict;
use warnings;

my %v;
$v{hourly_worker_expenses} =    { # elaborate on this !
								'all' => 16
				};

$v{hourly_worker_cost} = &{sub  {
								my $cost = 0;
								my $item;
								my %costs = $v{hourly_worker_expenses};
								#print %costs;
								foreach $item ($costs)
								{
									$cost += $costs{$item};
								}
								#print $cost;
								return $cost;
								}
						  }();


print $v{hourly_worker_cost};



##</code><code>##


Global symbol "$costs" requires explicit package name at test.pl line 13.
Execution of test.pl aborted due to compilation errors.


##</code><code>##

my %costs = \$v{hourly_worker_expenses};

my $costs = $v{hourly_worker_expenses};

my $costs = \$v{hourly_worker_expenses};

I originally didn't even mess around with the $costs/%costs hash and I tried to do the += with $cost and $v{hourly_worker_expenses}