Well, its obvious that the ability to at least see three cards deep is worth at least 1 mana (Compulsive Research and Thirst are 1 mana more than the baseline efficiency), but given the strength of these two cards, it is probably worth more
Many of the great preconstructed decks from the past two years are at very affordable prices, and are all fairly well balanced
However, the effect is inconsistent since it relies on random milling, making it generally weaker than more reliable enablers like Tome of Aetherwind (card draw), Lesson in Lava (damage plus filtering), or Aether Flarestyle direct damage instants that guarantee output without setup
He literally does the two strongest things you can do in the Commander format, and he does them super well
It's going to be an exciting day to see everyone get ripping their packs on launch, and I definitely won't be angry seeing a bunch of my chases pulled by others