It's that time again friends. A time where I share some more interesting rulings with you.
Are you lost... when you pay the [Cost]?
Well, be confused no more!
Question: If I have a card that reduces the gauge cost of my spells, may I cast a 1 gauge spell without paying any gauge.
Answer: Yes, you may! Reducing the cost of a card to nothing will enable it to be cast for free!
Question: If I have 1 life, may I cast a card that requires me to pay 2 life?
Answer: No. Unless you have a card which reduces the life costs of your spells (to my knowledge, only Rune Staff does this), you must pay the full cost of a card in order to cast it. If you don't have 2 life to pay, you may not cast that card.
Question: If I have 1 life, may I cast a card that requires me to take 2 damage?
Answer: Yes. Any amount of damage may be dealt to you, regardless of your current life.
Question: If I have 1 life and cast a spell that reduces the next damage I take by 2, can I cast a spell that deals 2 damage to me without dying?
Answer: Yes. Anything that would typically reduce damage also reduces damage paid in the [Cost] of cards.
Question: If I have a creature on the field that cannot be destroyed by card effects, can I cast a card that says, "[Cast Cost] Destroy one monster on your field."
Answer: Yes, you may. The [Cost] in this case is choosing a creature and applying the destruction effect to it. The [Cost] has been paid even if the destruction effect is not successful. This is similar to how damage reduction effects would apply to taking damage as a [Cost].