See use, strict, warnings.
See perlsyn, perlre, my, push, grep, printf, sprintf.

use strict; use warnings;
my (%items,@list);
while(<DATA>) {
    my @l = $_ =~/(\d+)\s([\w\s]+?)\s+([\d,]+)/;
    push @list,$l[1];
    $items{$l[1]}->{count} += $1; # bug?
    $l[2] =~s/,/./;
    $items{$l[1]}->{sum} += $l[2];
}
my %s;
for (grep {! $s{$_}++} @list) {
    $items{$_}->{sum} =~ s/\./,/;
    printf "%d % -9s %s\n", $items{$_}->{count},$_,$items{$_}->{sum};
}
__DATA__
1 PC BOX    20,0
1 PC Spare  32,0
1 PC Spare  5,2
1 PE Ak     100,0
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This should get you started. Don't use this as is, understand and improve it. Add code to test whether the array @l is really populated (i.e. the match succeeds), for instance.
Convert your $ to cents and back, because you don't want floating point operations dealing which currency.
Why the is the "bug" comment in there?