BuyDig via ebay is offering the Seagate Backup Plus 3 TB External Hard Drive for only $99 shipped. That’s $16 less than most other retailers and the lowest we’ve seen for it. Amazon sells it for $116 and over 1,000 of their customers rated it highly with 4/5 stars and great reviews. It features USB 3.0 for quick data transfer rates (upgrade to Thunderbolt technology or FireWire 800 with the available additional adapter.) Also, you can install the pre-loaded NTFS driver for Mac and use the drive interchangeably between PC and Macs without reformatting.
If you need a bigger drive grab this 4TB Seagate for $125.