Maarten D. de Jong
From the rules, page 7:
Note! If the player wants to keep both of the cards, he must place them one on top of the other. The top card is placed so that the top line of the card below is visible. The player chooses which card will go on top and which will go underneath.
Fields on Action cards always cost 2 Cash. This must be paid immediately, even if the field is placed beneath the other card of the Two-pack. (This is additional to the cost of the Two-pack.)