For one day only (3/5/09) J&R.com has cut the price on the Western Digital 500GB My DVR Expander hard drive (model no. WDG1S5000VN) from $199.90 to $99.91.  That's a price reduction of $99.91 making this the lowest price we could find on this hard drive by about $12.  Shipping rates start at around $6 and vary by your location and method of delivery.  Sales tax applies for New York residents. 
 

Instantly add space for up to 60-hours of HD video or 300-hours of standard definition TV with the Western Digital My DVR Expander hard drive.  It is designed to connect to an eSATA-enabled DVR to add an extra 500GB of storage space.  It has been tested or compatibility with the Scientific Atlanta 8300 series and TiVo.  It is backed by a one year limited warranty from Western Digital.  Dimensions: (H) 6.78" x (L) 5.36" x (W) 2.23" ; weight 2.6lbs.