Ebay offers WD Blue 4TB Internal SATA Hard Drive for $65 (reg $109.99) with free shipping. 

Product Description:
SATA interface; Acronis True Image WD Edition software; data transfer rates up to 6 Gbps
Store edited photos, videos, and games on this 3.5-inch Western Digital hard drive. It has dynamic cache for optimizing allocation between reads and writes, and there's plenty of space to store files with its 4TB capacity.