This question already has an answer here:
Babylon: When you have the second stage of the wonder that allows you to buy your last 2 cards in the age instead of discarding, does this count as 1 turn or as 2 separate turns? Here's why I ask... I needed to buy glass from my neighbor. Each card needed me to buy a glass, and he only had 1 glass. If the cards count as 1 turn, I could only buy 1, and would have to discard the other card to collect 3 coins. If the cards were 2 turns, then I would buy the glass twice in 2 separate transactions. After 15 minutes debate, our group voted that it was 2 turns. But we would like to know what other people think.