In Deckbox Tibalt, the Fiend-Blooded shows up with price to be $0.00
http://deckbox.org/mtg/Tibalt,%20the%20Fiend-Blooded

But in the TCG Player website it shows up with "correct" values.
http://store.tcgplayer.com/magic/duel-decks-sorin-vs-tibalt/tibalt-the-fiend-blooded

The issue might be with TCG API.

Cheers

There are more cards with this issue. Lim-Dûl the Necromancer, for example.

Both issues are likely due to the API. Please refer to the Known Issues and Requests thread.