You are buying this screen for game days, movie nights, and years of living room gatherings, so you want to get it right the first time and not replace it in three years. An 85-inch OLED is a massive centerpiece, and the trick is making sure the picture quality and size justify the wall space.
Late January right before the Super Bowl is the sweet spot because retailers slash prices to clear out floor space for the new spring models coming in. Last year's top-tier models drop hard in price right now while still offering almost identical performance to the brand-new releases.
That intro window is a hard deadline, not free money, so if you still have a balance left when the 15 months are up, standard interest kicks in on the whole original amount.