Here's a rules question that came up in a game. I visit Iron Age and score a card. I rule 3 times, so I should get a discount of $6. However, I'm scoring a card that only costs $4. However, I have Tactician, and I use it to pay $4 more to advance an extra crown.

Do I pay $2 or $4?

There's a similar question regarding the interaction of Tactician and Pilgrims.