LightInTheBox offers the Nitecore Tube LED Keychain Light in several colors (Black pictured) for $5 with free shipping. (Choose "Postal Service - No Tracking" during checkout.) That's a buck under last week's mention and the lowest price we've seen. (It's the best deal now by $3.) It features two brightness levels with up to a 45-lumen output and a rechargeable Li-ion battery with up to 48 hours of run-time per charge.
Note: This item ships from China and may take two to five weeks to arrive. Uncheck "Add shipping insurance to your order" during checkout to remove the 49-cent fee.