For me the word Cheap and lights shouldn't really come together.
Ah, well, if you're only riding in lit areas, I can see the advantage of getting some cheap minimally-legal blinkers to leave on the bike and if they get nicked then you replace them for less than a fiver.
There are so many out there at the moment, think of it as an investment to your health , so buy the best you can really.
To your health? I don't think any of the suggested lights will irradiate you!
Are you thinking that people hit under-lit cyclists more? They don't. I can't find the more detailed report about the study just now, but
this one says 2% of collisions had no lights as a factor and IIRC, defective lights was a tiny fraction of that, maybe a handful of incidents. I'm pretty sure far more than 2% of cyclists are going around unlit (even at my most optimistic, I'd say it's no less than 1 in 25, which is 4%), so they're actually underrepresented in collisions, which is curious.