They really are unebleivable aren't they. They say they won't pay any more than £35 million for Cesc, and then they add a buy-out clause to Thiago of £81 million, meaning that is what they value him at, as they can't sell for less. Cesc is obviously better than Thiago, and Wenger should use this to tell Cesc that Barca only want him so that no one else has him, not because they think he will play.
Don't think their release clauses have anything to do with their price valuations. Just some weird spanish contract thing.