A few times ago.... summer I think last year... there was a family trying to add a room to a reservation. Disney is almost always going to have "a room" available, but as was the case on that trip, they charge full rack rate. At the value resorts, this can still gat way upwards of $100 (don't think I've ever seen them over $200).
Jan '07 Pop Century, Mar '07 Day Trip, April '07 Off Property, May '07 OKW, July '07 POR, Oct '07 Pop Century (& MNSSHP!!!), Dec '07 Day Trip
Jan '08 POR
Feb '08 Pop
Mar '08 Off Property
April '08 AS Sports - I think - still gotta book it