For commuting, anything tha has 300 lumens is good enough.
Only if you have very well lit streets on a clear night then you could get away with 300 lumens but for the prices of lights today I still recommend getting a light that puts out at least a max of 700 lumens, this means it can be turned down if you desire, but having at least a 700 L capacity allows you the option to ride on dark rainy nights, or on streets with very little to no street lighting; if you don't buy a higher power light than 300 L and someday you're riding on less than idea conditions you'll wish you had the brighter light which means you'll go out and have to buy another light, why bother doing that? just get the light with the power now. Also the faster you ride the more power you'll need, a person can over run a 300 lumen light.
Don't believe me about the lumens? Ok, instead take a look at this website of beam comparisons:
http://reviews.mtbr.com/2014-mtbr-bike-lights-shootout-tunnel-beam-patterns, click on any photo and the detail of the lumen being used and the brand of the light is given, for example the third light on the top row from the left is a 300 lumen light that was actually rated at 349. This is an older 2014 comparison and most of the models have been changed since then but it should give you an idea of the type of beam pattern and brightness of the various lumens so you can decide what you think you might need. Also this is the view of how the camera sees it, the human eye is far different, but again it's just a representation to give you an idea.
Lezyne sells a 800 lumen light for $65, Cygolite has one for $52, yet for a 300 lumen light Cygolite has one for $50? for just two more dollars you can get 400 more lumens! Lezyne has a 350 lumen light for $33 (sale price) so for just $33 more dollars you get 450 more lumens; so they're not that much more expensive and you won't have to go and buy a second light later and end up spending even more money. Some of the name brand lights will offer a light with the same lumens as another model of theirs but will be cheaper, why? they put a lessor quality battery in the cheaper one, so you have to know how long you want your light to last, say an hour, so then buy a light that will run on the brightest setting for an hour knowing most of the time you may run at half power extending the battery run time so you don't run out of juice by chance on a ride.
A person could buy those no name brand generic lights, but be forwarned, their lumen ratings are way over stated, if they say it puts out 1000 lumens expect 300 to 400 max lumen range with an odd shaped beam pattern, and expect batteries to last about 1/2 as long as they claim, not to mention other issues like some catching fire when recharging. Sticking with name brands gets you lumen ratings that are usually within 50 lumens of being stated on the carton, and the battery life is usually spot on, plus hassle free warranty. The only generic light that I would remotely consider is this one:
https://www.amazon.com/Bright-Eyes-Rechargeable-Bike-Headlight/dp/B00X90ZYJ0/?tag=reactual-20 and that's because it has a lot of high reviews and was favorably reviewed independently.
I mentioned Cygolite and Lezyne only because I own their products and their products are rock solid, there are other brands that are also very good and probably rock solid as well, like Cateye, Light & Motion, and Niterider, but I have no experience with the other brands except for L & M Vis 180 tail light which is a very good product.