Taking a break from all the New Announcment threads and was reading over the Prestige Enhancements and thought I would throw out a short 'Cost' list as I found it pretty interesting.
I tried to use the cheapest way to get each one and the cost is calculated for Tier 3 on all of them.
Assassin: 38 AP's, No Feats
Hunter of the Dead: 35 AP's, No Feats
Defender of Sybrys: 32 AP's, 1 Feat
Knight of the Chalice: 24 AP's, No Feats
Kensai: 34 AP's, 5 Feats (Note: All feats but one have Figher level requirements)
Stalwart Defender: 26 AP's, 1 Feat
Frenzied Beserker: 30 AP's, 1 Feat
Tempest: 14 AP's, 7 Feats (Note: 3 of these you gain as Class Features)
This may have been posted elsewhere and apologize for the redundancy if it has.