You need a headset that blocks out the dog, the lawnmower, and the neighbors so you can actually hear on calls. If you buy a cheap pair now, you will just be replacing them by next spring, so we are aiming for something in the $250 range that is built to last.
August is prime time for back-to-school sales, which means audio gear sees plenty of price cuts. Watch for brands dropping new versions right now, because that is your cue to grab last year's model at a steep discount without losing any real performance.
That 0% intro APR is a deadline, not free money, so make sure your $250 balance is completely gone before those 15 months run out or you will get hit with standard interest on what is left.