This light can be found for $10-13 (and comes with a taillight) - making it one of the cheapest ways to get lighting on your bike. However, it scored very low in our brightness and beam quality tests and does not have a USB rechargeable option.
BV SuperBright Review
Cons: Very poor beam quality, not USB rechargeable.
Our Analysis and Test Results
This had one of the lowest beam quality scores of any light we tested and only got a 1 out of 10 rating. while this light is relatively bright for its price, it shines a very narrow beam that is not that effective at illuminating your peripheral vision. As you can see below, compared to the Metro 400, the pattern is quite narrow.
This light had one of the highest brightness scores for a super cheap model. It shined 52 m in our tests, which is much farther than any other sub $20 light we tested. That said, as mentioned above, the light is so narrow that it illuminated very little of the bike path, as you can see below compared to the Metro 400.
This light gets a 6 out of 10 score for battery life. That is not bad, but it was one of the lowest scoring lights that did not have USB rechargeable capabilities. It lasted 9.2 hours on four AAA batteries. If you were to commute a lot with this light, replacing the batteries would get expensive and quickly mitigate its original low price over time.
This light is relatively light, small and easy to install. But it is not nearly as easy to remove with one hand as other lights.
This is one of the cheapest lights with a decent maximum beam distance. That said, the long-term value is poor if you use it a lot and replace many AAA batteries.
If you don't ride at night much and are looking for the cheapest way to get a headlight and tail light on your bike, and don't mind the poor beam quality, this might be an option. However, if you commute much at all, we highly recommend spending more money and getting a light that is both USB rechargeable and has better brightness and beam quality.
— Chris McNamara