I imagine it will be super expensive, yet worth it if you have that kind of money!
There’s a report going around quoting $3,300 for the full three-day experience for a single occupancy cabin or $7,200 for a cabin with five passengers. Keep in mind, though, that even if these reports are accurate to what’s currently being discussed (dubious), we’re at least a year and probably a recession away from this thing opening. Nothing is set in stone yet.
Also worth noting is, despite being commonly referred to as a hotel, this will be more like “what if Sleep No More was on a cruise ship?”, so expect pricing closer to a cruise than a typical hotel.