How to save 10+ resources to play a bad card:
- Step 1: Be Father Mateo.
- Step 2: Have Shining Trapezohedron in play.
- Step 3: Play Absolution with X equal to the number of chaos tokens in the bag minus 3 (or just infinity, it doesn't really matter).
- Step 4: Automatically succeed at the skill test on Shining Trapezohedron via either The Codex of Ages, Beloved/Paradoxical Covenant + Favor of the Sun/Favor of the Moon.
- Step 5: Heal a ton of horror or fill the chaos bag with bless tokens, which you could have done way easier with better cards. But hey, you saved between 10 and 20 resources, achievement unlocked!
The other X card I found is Explosive Ward, but that has an even stricter upper limit (your empty arcane slots) so there is not much money to save there.
Honestly, I wanted to theory-craft ways to cheese this card, having discovered you can commit the card you are discounting to the test, but it's apparently harder than I thought. You get at maximum +2 to the skill test without further shenanigans like Bestow Resolve, which is just that.