Best Buy offers the Mophie Space Pack 32GB Charging Case for iPhone 5/5S in White, model no. 2618_SP-IP5-32GB, for $99.99 with free 2-day shipping. That's $8 under last month's mention and the lowest total price we could find by $10. It features 32GB of extra storage integrated with the rechargeable battery case; up to 100% more battery life; LED battery indicators; and an app to directly access stored files, music, and videos.
Need it by Christmas? Orders placed by December 22 at 11:30 am ET are guaranteed to arrive on December 24.