This is a simple LED growth light to better grow my chili plants in winter. It has 2 mounting options (vertical/horizontal). Power is provided over USB, so it is portable too. The base is 3d printed with a simple layout printable in PLA. Overall costs are below 10$.

Supplies

Flat aluminium bars can be found in DIY stores, any 3mm thick bar will do
USB LED Grow Light is available here under 5$
free .stl file for 3d printed base

Step 1: LED Bar

First stick the LED strip centrally on a 3mm flat bar. The LED strip has adhesive tape on the back.
All flat bars with 3mm thickness will fit. Use a metal bar to keep the LEDs cool. I have used a 1000x50x3mm flat aluminum bar.
Make sure that you have sufficient excess power cable to plug the USB into a power port.

Step 2: 3d Printed Base

3d print the base. I used PLA+, simple PLA should work too.
The file can be downloaded for free https://www.thingiverse.com/thing:5141775 Printing with 25% infill takes around 5.5 hours. The base is more robust when using 100% infill.

Step 3: Vertical Mounting

The 3d printed base features two 3mm slots for vertical and horizontal installation. Use the slot on the topside for vertical mounting. There is no support which need to be removed.
To secure the base, simply put weight (eg powerbank) on it.

Step 4: Horizontal Mounting

The 3d printed base features two 3mm slots for vertical and horizontal installation. Use the slot on the side. 2 supports need to be removed before installing.
To secure the base, put weight on it. Depending on the weight of your light bar a power bank might not be enough. Use additional weight.