Consider the Sony SVRHD700 Digital Video Recorder. This fine-looking piece of kit has dual high-definition digital TV tuners, HDMI output and a 160GB hard drive to store up to 23 hours of HD video. The even finer Sony SVRHD900 is identical — except for a 250GB hard drive, storing 36 hours.
Now a 250GB hard drive costs just $30 more than a 160GB. But by adding $30 of hardware, Sony can charge an extra $200 for the whole machine — $1499 compared with $1299.
Why? Because you get 56% more storage, and 20% more model number, but pay only 15% more. Bargain!