Your input is simple enough that you could parse it using split, but for anything more complex, you should heed kennethk's advice. Here is the parsing piece; I'll leave the printout as an exercise for you: 
use strict;
use warnings;
use Data::Dumper;

my %data;
while (<DATA>) {
    chomp;
    my ($lot, undef, $make, undef, $city, $state) = split /,/;
    $data{$lot}{$make}++;
    $data{$lot}{location} = "$city,$state";
}
print Dumper(\%data);

__DATA__
lot1,new,honda,civic,cincinnati,oh
lot1,used,chevy,impala,cincinnati,oh
lot1,new,honda,civic,cincinnati,oh
lot1,used,chevy,impala,cincinnati,oh
lot1,new,cadillac,escalade,cincinnati,oh
lot2,new,buick,sentry,houston,tx
lot2,used,ford,ranger,houston,tx
lot2,new,buick,sentry,houston,tx
lot2,used,ford,ranger,houston,tx
lot2,used,ford,ranger,houston,tx
lot3,new,ford,ranger,lexington,ky
lot3,used,cadillac,escalade,lexington,ky
lot3,used,cadillac,escalade,lexington,ky
lot4,new,ford,f150,chicago,illinois
lot4,new,ford,f150,chicago,illinois
lot4,new,ford,f150,chicago,illinois

[download]

which prints out; 

$VAR1 = {
          'lot3' => {
                      'location' => 'lexington,ky',
                      'ford' => 1,
                      'cadillac' => 2
                    },
          'lot1' => {
                      'location' => 'cincinnati,oh',
                      'cadillac' => 1,
                      'chevy' => 2,
                      'honda' => 2
                    },
          'lot2' => {
                      'location' => 'houston,tx',
                      'ford' => 3,
                      'buick' => 2
                    },
          'lot4' => {
                      'location' => 'chicago,illinois',
                      'ford' => 3
                    }
        };

[download]

In reply to Re^3: What is the best way to handle this data? by toolic
in thread What is the best way to handle this data? by terminaljunkie

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