sorry, I'm tired and it smells like homework...

So here only a stub for you to work on:

(Showing how to use a HoH to represent a table)

use strict;
use Data::Dumper;
 
my (%h,%x,%y);
 
scalar <DATA>;
 
while(<DATA>){
  chomp;
  my ($id, $size, $qty, $price)= split /\s*,\s*/,$_ ;
  $h{$qty}{$size}=$price;
  $y{$qty}=1;
  $x{$size}=1;
}
 
for my $y (sort keys %y) {
  for my $x (sort keys %x) {
    if (exists $h{$y}{$x}) {
      print "$h{$y}{$x}\t";
    }else {
      print "\t"
    }
  }
  print "\n";
}
 
__DATA__
id, size, qty, price
1 ,  1  , 100, 43
2 ,  1  , 250, 52
4 ,  2  , 100, 45
5 ,  2  , 250, 55
6 ,  3  , 100, 50
7 ,  3  , 250, 56
8 ,  4  , 200, 55
9 ,  5  , 250, 61
[download]

OUTPUT:

43    45    50            
            55        
52    55    56        61
[download]