Seems that you might not be asking about the individual LED bulbs or lamps, but the entire fixture.
A while back, the local 99 cents or dollar stores had some simple light fixtures at a great price (compared to ~$8 online).
They might have had 3 to 5 LEDs and used two AA batteries.
For headlights, I also like the simple 9-LED aluminum flashlights, with three AAA batteries, and attached to the handle bars with cushioned loop clamps. [Need to be careful with those, that they don’t point into the drivers’ eyes].
For safety (versus price), I believe that there was a “Flare” rear taillight model with a bunch more LEDs, that some claimed to be more visible in broad daylight.
I purchased one of those more expensive rechargeable headlights with strobe mode, (came in black or Bianchi turquoise), and it was so bright, (and sometimes hot), that I moved it from my bike to my toolbox.
For the orange bike pictured above, one might consider how the lights would be mounted yet visible to traffic. Perhaps adding a Pletscher rear rack would make room for the tail lights and storage stuff?