You can not tell. But no. It's three days ago a meticulous calculation published on Reddit by the user Seaserpento2, entitled "How Much Does It Cost To Travel To A Gore?". On the post in question the user explains that he has created a program on Python which simulates the opening of packs, transforms duplicates into dust, collects cards and stops the count of packs once a certain amount of cards and a sufficient amount of dust have been collected to craft the rest. We remind you that Hearthstone: Journey to Una Goro introduces 135 new cards, including 49 common, 36 rare, 27 epic and 23 legendary.

Hearthstone: Travel to A Gore
After several attempts, according to its calculation, the amount of minimum packets to complete the collection would be 214, while the maximum amount 437. Taking it as a standard the average of 316 packages and referring to Blizzard prices ($ 49.99 for a bundle of 40 packages, 8 would be needed) the calculation is fast and exaggeratedly high: about $ 399.92. This is where you say "good".

To leave no doubt Seaserpento2 has made available the source codein case you want to do yourself a try.
In any case, whatever the price you were to come out of, the warning I feel about doing is this: DO NOT spend to win. On the other hand, in a game like this, you can have all the existing cards and continue to have no skills to use them.