Through its Deal Zone, B&H currently has the B+W Kaesemann Circular Polarizer MRC Filters for about more than half off for the rest of the day (until midnight ET). The 77mm size is just $49.95 (58% off of $119.95 normally) while the 58mm size is also available for $29.95 (67% off of $89.95 normally). The B+W brand is a well-known, high-end filter brand, and its multi-coated Kaesemann filters are its own gold standard.
Update: I'm really sorry for anyone getting to this now, but they've already sold out, unfortunately. That was a sweet deal. Hopefully they'll have something like it again soon.
Perhaps with the D850 out, now you'll want to stock up on the best polarizing filters you can for your high-end landscape photography. Of course, while the 58mm size is still popular, it's the 77mm size that covers virtually all of the most common pro-level lenses such as most of Nikon's 1.4G gold-ring-series lenses and Canon's L-series glass, too. For lenses such as those in Nikon's well-loved and more affordable 1.8G series, a step-down ring to the common 67mm filter size for those could have you covered so your 77mm filters would still work (this would be great, too, for future expansion if you ever decide to buy into any 77mm-filter-ring glass.
Personally, I haven't seen a deal this good on these filters before. Even on Craigslist or eBay, I've often seen these go for at least $60-80 used. Jump on it now if there's a chance you might use it.