Western Digital offers the Western Digital Caviar Green 2TB Serial ATA 3Gb/s Internal Hard Drive, model no. WD20000CSRTL, for $99.99 with free shipping. That’s $38 under our July mention and the lowest total price we could find by $23. This “green” product promises reduced power consumption compared to other models by up to 40%. It features a 32MB cache and runs at a variable rate of 5400 rpm to 7200 rpm.