Mulcolor via Amazon offers the Holan 12-LED Motion Sensor Solar Waterproof Wall Light for $12.99. Coupon code "GVAKCOML" cuts that to $7.92. Plus, Prime members bag free shipping. Excluding the below mention, that's the lowest price we could find today by a buck, although we saw it for $1 less in January. (For further comparison, we saw two lights for $12 three weeks ago.) It automatically turns on at night and features a 120° motion sensor with a 15-foot range, and built-in solar-charged 1,200mAh Li-ion battery with up to 12 hours of run-time per charge.
Don't mind waiting on your deal? iTechcool via eBay offers a similar item for $7.05 with free shipping. This item ships from mainland China and requires two to five weeks for delivery.