for my $transactionType (sort keys %$results)
{
  for my $purchasedThings (sort keys %{ $results->{$transactionType} }) # Curlies here to mark out what to dereference
  {
    printf("spent \$%5d on %20s using %20s\n",
      $results->{$transactionType}{$purchasedThings},
      $purchasedThings,
      $transactionType,
      );
  }
}