Something like $3 to $5 for a paper refill for a day planner in a metal ring binder?
I forget, but every X years the position of the days repeats and starts over again. I was thinking of every 26 years or something like that, but I am unsure of the range. Get a planner from the 1970's and it may be in the same position as the current year. :)
I got an old Timex DataLink watch (TDL100), and a Royal Data Link PDA organizer. It needs Windows 95 or 98 to synch, without needing the laptop adapter. The Royal is out of batteries, but the watch works great.