I have found that the best way to maximize my points when I want to cruise is to rent out the points and then book the cruise on cash.
Figure out how much cash it is for the cruise. Say, it's $4,500. At $10/pp, you only have to rent out 450 points to cover the cost of the cruise. Othewise, it may cost you over 700 points to book it as a points-only cruise.
I did that for a cruise we have planned for next spring. The points cost is over 300, yet the cash price is $1,700. So, I rented 170 points and paid cash for the cruise, leaving me with enough points to go to WDW for a few days prior. I've used David's rental service and the process is SO easy and safe.
We have done this as well for 3 cruises. But for a true cost you need to add in the yearly dues to get a true cost calculation. With the dues eating 5 dollars out of the rental income the 450 point becomes 900 points making 700 a reasonable deal. Just my opinion but I may be way off base

