Amazon has Led String Lights, Party Decorative Lights Salt Water or Seawater Self-powered 66 fts Waterproof Twinkle Lights for Indoor Outdoor and Seasonal Holiday (4 Colors Shining Lights for $8.99. Shipping is also free.
Price: $8.99
Code:A5IO2PWR
The cool thing about this is that it is self-powered using salt-water. No plugs or battery required.
https://www.amazon.com/dp/B01M0X94RW