Normalization and regexp

Hi,

Since Canada Post hasn't programmed their automated web tools for calculating transportation costs to work with
anythingoutside of Windows Internet Explorer, I'm obliged to write a web based program optimized for all those *other*
browsers,myself. Part of this task requires that I set up tables in postgresql that match postal codes to
transportationcost.  

Canada Post provides a booklet for calculating transportation cost based on package weight and the first three
charactersof the postal code sequence. For instance, if I want to send a package to an address that includes G8F 1X1 as
thepostal code, I take the first 3 characters G8F and look them up in table 1. 

Table 1

PostalCode    Tarrif number
---------------------------
G4V               14
G8E-G8G           14
G4R-G4S           13

Since G8F falls in the G8E-G8G range, I now know that the tarrif number is 14. Taking the number 14, I go to table 2

Table 2

   For tarrif Code 14
Weight(kg)       Price
----------------------
  1.0            5.37
  1.5            5.61
  2.0            5.82

If the weight of my package is 1kg, the price is 5.37 to send the package to the address bearing G8F as the first 3
charactersof the postal code. 

To render this in the database, I have done the following:

_____________________________
           p_code            |
=============================
  pcode_id   |     tarrif    |
-----------------------------
    G4V      |       14      |
-----------------------------
    G8E      |       14      |
-----------------------------
    G8F      |       14      |
-----------------------------
    G8G      |       14      |
-----------------------------
    G4R      |       13      |
-----------------------------
    G4S      |       13      |
-----------------------------

__________________________________
           price_weight           |
==================================
   tarrif   | weight(kg)|  price  |
----------------------------------
     14     |    1.0    |   5.37  |
----------------------------------
     14     |    1.5    |   5.61  |
----------------------------------
     14     |    2.0    |   5.82  |
----------------------------------
     13     |    1.0    |   5.20  |
----------------------------------
     13     |    1.5    |   5.32  |
----------------------------------
     13     |    2.0    |   5.42  |


Therefore my sql statement would look something like this:

SELECT price FROM price_weight
WHERE p_code.tarrif = price_weight.tarrif
AND pcode = 'G8F'
AND weight = '1.0';

I think this will work, but before I proceed, I'd like to ask 2 questions:

1.
Is it possible to further normalize the data in the p_code and price_weight tables above?

2.
Is it possible to abbreviate the number of records in the p_code table using regular expressions. For instance, to
avoidrepetition, I thought I'd use regular expressions, so that instead of entering the postal code into separate rows
assuch: 

G4V    14
G8E    14
G8F    14
G8G    14

I could do something like this:

(G4V | G8[E-G])    14

Somehow I don't think this is possible, but I'm looking for any way to minimize the number of postal codes that I have
toenter, since there's a lot of them. 

Anyway, I realize these questions may have more to do with database design than postgresql per se. If there's a better
placeto ask them, please point me in the right direction. 

Thanks,

Mark