Here's a simple battery-powered, portable and flexible LED string solution. 3 meter, ~3cm spacing, powered by 3AA cells. Ideal for quick "BLING" effect!
The battery-box LED String is really quite brilliant, with an LED located every 3.3 cm over 10' for a total of 90 LEDs. Available in a multitude of colors, they're a quick and easy way to add some LED bling to your project, with no soldering or hacking required. As opposed to regular 3m 90 LED Strand with Battery Box which are thin enamel wire, these are super flexible and perfect for wearable applications. The RGB version is a true RGB preprogrammed to cycle through the rainbow of brilliant colors.
Flexibility comparison and RGB string demo: