Um, there is only one suite in Cinderella's Castle and it isn't available to rent. I think the sweepstakes to possibly get in the suite is over, so nowadays it isn't open at all to the public. :look:
Unless you're Tom Cruise or someone with an vault full of gold coins you can throw around Disney's way and rent out the suite for a night, more of like a VIP perk type thing is still possible but to the average folk its super rare to even get a glimpse in there.