Amazon has the Bose QuietComfort 35 (Series II) on sale today for $299. That is good for $50 off of the regular price of these. Now while Amazon already has the first-generation of the QuietComfort 35 headphones on sale for this same price, this is definitely a better deal. As it sports slightly better battery life, but perhaps more importantly, it also has Google Assistant included. Allowing you to talk to the Assistant through your headphones.
The Bose QuietComfort 35 (Series II) is one of the best pairs of headphones available, especially if you're looking for a pair of noise-cancelling headphones. These headphones will offer up some great noise cancelling, which makes them great for taking on the go with you - particularly if you are flying. The battery life here is pretty impressive, even with noise cancelling turned on, coming in at around 20 hours on a single charge. Now if you turn off noise cancelling, you can get around 40 hours of continuous playback on a single charge. Bose does have a 3.5mm jack here, so you can also use these as a pair of wired headphones if you wish. These headphones do have some pretty good audio quality, that you do expect from Bose. You're going to get some rich audio here, with some good bass, mids and highs, without any of these overpowering the others. Which you might see from other headphones.
This item is also eligible for Amazon Prime's free shipping. Which includes free two-day shipping, and pretty cheap (usually $3.99) next-day shipping if you need it extra fast. If you are not an Amazon Prime member yet, you can sign up for a free trial of Amazon Prime. You'll get 30 days free (if you're a student, you get 6 months), and then it's $119/year (or $59/year for students). Prime members do get a whole lot more than just free shipping though, so be sure to check out the full benefits.