For context as to the sheer magnitude of this cost, an Exceptional Story costs 45 Fate.

It's difficult to think of a case where this would ever be worth it. Well, I guess maybe for <a href="/wiki/The_Catafalquerie" title="The Catafalquerie">The Catafalquerie</a> at Christmas for the Tears (a 312.5e item is nothing to sniff at), but even then the Cave being card-based means that you still run the risk of the whole thing being pointless.