A good multi-room speaker setup should last you a decade. Since audio tech does not age as fast as phones, buying last year's flagship model right before Black Friday is usually the smartest move. You get the same deep sound and reliable connection for a fraction of the price, and you won't need to upgrade anytime soon.
If you are looking at an $800 price tag, you do not have to drop all that cash at once. By using the Citi Simplicity® Credit Card, you can split that cost into monthly payments of $44.44 and pay no interest for a year and a half.
Keep in mind that the 18-month window is a hard deadline, not free money. If you still have a balance left when those 18 months are up, the standard variable APR will kick in on whatever is left, which will quickly erase any deal you got.