LightInTheBox offers the 6.6-Foot 20-LED Bottle Fairy String Lights 6-Pack in several colors (Multicolor pictured) for $8.49 with free shipping. (Choose "Postal Service - Tracking" during checkout.) That's the lowest price we could find by $3. Each string features a cork-shaped battery housing and waterproof wire and requires three button batteries (included). The pack comes with a screwdriver. (Bottles aren't included.)

Note: This item ships from China and requires three to four weeks to arrive. Uncheck "Add shipping insurance to your order" during checkout to remove the 49-cent fee.