A good pair of active noise-canceling headphones is about blocking out the world so you can actually focus or enjoy music without cranking the volume. When you spend around $250 on a set, you want something that lasts five years or more, meaning you only buy once instead of replacing a cheap pair every six months.
We should look at the release cycle before you drop any cash because audio brands drop new flagship models every fall. That is usually when last year's version gets a steep discount for doing essentially the same job.
That 0% window is a deadline, not free money, so if you still owe a balance when the 18 months are up, you will get hit with interest on the remaining amount.