You can get equivalent of 50% off at your local Sony Store at the mall.  This is not a well-publicized promotion and it may vary slightly from location to location.  Here are the steps:

• Call your local Sony Store at the mall to confirm that they will match the mall's Gift Card up to $100.  Chances are very good that they will.  We have yet to talk to a Sony Store that does not participate in this promotion.
• Assuming you plan to spend $200 in the Sony Store at your local mall
  • Go to the same local mall's Customer Service and buy a $100 Gift Card for the mall
  • Go to the Sony Store in the same mall and buy your item, originally at $200, for just $100, effectively taking 50% off.

We have talked to about 10 different Sony Stores across the country, and all of them confirmed that this is an going promotion.  Some stores have said that this Gift Card-Matching Promotion has no exclusions and this would even work on PlayStation 3.  A few have said that it works on everything except PlayStation 3.  Note that all of them have all confirmed this would work on sale items too.  One store has told us that this promotion ends on 1/1 while another said possibliy this weekend.  The inconsistency has led us to believe that this promotion could be pulled at any time so it's a good idea to take advantage of it when it's still available.