A high-end wireless mechanical keyboard is meant to fix your wrist pain and last for a decade of typing. When you spend this much, you are buying once instead of replacing cheap plastic boards every couple of years.
Watch the release cycles closely because major holiday sales events are your best friend here. If a brand drops a new version, last year's model instantly becomes the better buy at a steep discount while still offering the same solid build quality.
Just remember that the intro window is a hard deadline, not free money. If you still carry a balance when those 18 months are up, deferred interest or standard rates will kick in on whatever is left.