You are buying these for daily focus, travel, and years of listening, so we want to get a pair that lasts rather than replacing a cheap set in twelve months. Mid-summer tech sales are a sweet spot because last year's flagship models get marked down right before autumn replacements drop.
We are looking at about $400 for a top-tier pair of over-ears. If you time the sale right and space out the payments, you can grab them without taking a hit to your cash flow.
Remember that the 0% intro APR is a deadline, not free money. If you still have a balance left on the card when those 15 months are up, interest will kick in on the original amount from day one.