This 5-metre long, flexible, addressable, waterproof strip contains 60 LEDs per metre, for a total of 300 RGB LEDs. Power consumption is 18W per metre.
The strip can be cut at any length. Further lengths can be achieved by soldering the ends of two strips together.
WS2812B is the de-facto standard for RGB LED strips, and will allow you full control, using either a ready-made controller, or a DIY microcontroller.
Each LED is made up of Red, Blue and Green diodes, each of which is rated at 20mA, so at full brightness, this strip pulls 60mA per LED, which quickly adds up.
For installations, we have power adaptors. For portable use, we have power banks.