Added on 11-Oct-2000
A rough estimate of the cost of the Platinum Collection is on the HMV website.The price listed at http://www.hmv.co.uk is £24.99 - but as they sell the big Freddie set for £96.99 and the 3CD Freddie set for £15.99 it should be available for less elsewhere.
As far as I know it can't be ordered on there yet - it says its not available until the release date (Nov 13th).
There's also a picture of the front cover. It has the same crest as Greatest Hits 2 and the Hits 1 and 2 Set. Following Greatest Hits 3, the colour of the background is silver and the crest and text is black.
It is definitely the 3 greatest hits albums in a 3CD set. There is no mention of any bonus tracks on the front, but I suppose we can still hope!