You can store each price in a list, and all the lists in a hash: 
my %prices;

# read all files:
for $fn (@files){
   open (my $file, '<', $fn) or die "Can't open '$fn' for reading: $!"
+;
   while (<$file>){
      chomp;
      my @items = split m/;/, $_;
      push @{$prices{$items[0]}, $items[1];
   } 
}

# print output:
for my $k (sort keys %prices){
    print "$k;", join(';', @{$prices{$k}}), $/;
}

[download]

This works for an arbitrary number of files, but if some prices are only present in some files, the result doesn't show which prices comes form which file.

In reply to Re: hash table with three input files by moritz
in thread hash table with three input files by steph_bow

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