Best Buy via eBay offers the myCharge Transit Plus 3,000mAh Power Pack, model no. TR30K-A, for $9.99. Opt for in-store pickup to dodge the $6.98 shipping charge. That's $5 under our January mention and the lowest price we've seen. (It's the best in-stock price today by $14.) It features a fold-out car adapter and 2.4-amp USB output.