Is it possible to cast 2x Final Payment while sacrificing just one creature? [duplicate]

Question

Situation:

1. Player A controls 2 creatures.
2. Player B controls 1 creature.
3. Player B plays 1x Final Payment and declares his creature as additional cost.
4. Before resolving the spell, Player B plays another Final Payment, once again declaring his creature as additional cost.

What happens here?

• Option 1: Only the second Final Payment is executed since the additional costs for the previously casted spell aren't paid.
• Option 2: Both creatures of Player A are destroyed while Player B only sacrificed one creature.

I suppose it's option 1 but we had a draft the other day where my opponent claimed that option 2 would be correct.

Answer 1

Step 4. is not possible; sacrificing the creature is part of the cost of the spell, so it is done while the spell is cast, not when it resolves. Player B just cannot play the second Final Payment and the card stays in his/her hand; only the first Final Payment is executed.

117.8. Some spells and abilities have additional costs. An additional cost is a cost listed in a spell's rules text, or applied to a spell or ability from another effect, that its controller must pay at the same time they pay the spell's mana cost or the ability's activation cost. Note that some additional costs are listed in keywords; see rule 702.

601.2. To cast a spell is to take it from where it is (usually the hand), put it on the stack, and pay its costs, so that it will eventually resolve and have its effect. Casting a spell includes proposal of the spell (rules 601.2a-d) and determination and payment of costs (rules 601.2f-h). To cast a spell, a player follows the steps listed below, in order. A player must be legally allowed to cast the spell to begin this process (see rule 601.3). If, at any point during the casting of a spell, a player is unable to comply with any of the steps listed below, the casting of the spell is illegal; the game returns to the moment before the casting of that spell was proposed (see rule 721, "Handling Illegal Actions").

Answer 2

601.2. To cast a spell is to take it from where it is (usually the hand), put it on the stack, and pay its costs, so that it will eventually resolve and have its effect. Casting a spell includes proposal of the spell (rules 601.2a-d) and determination and payment of costs (rules 601.2f-h). To cast a spell, a player follows the steps listed below, in order. A player must be legally allowed to cast the spell to begin this process (see rule 601.3). If, at any point during the casting of a spell, a player is unable to comply with any of the steps listed below, the casting of the spell is illegal; the game returns to the moment before the casting of that spell was proposed (see rule 721, "Handling Illegal Actions").

As per the rules, do you ever cast a spell and wait for it to resolve before you tap your mana? or does the spell only go on the stack when you pay for the mana?

The rules clearly say that you need to meet all of the casting costs, so if you want to cast Final Payment you need to have all of the costs to cast it, this means, if your life is at 4 an you control no creatures you are unable to cast it, even if your opponent was to take over your turn (by the means of cards like emrakul, the promised end or such) and tried to cast Final Payment to for you to lose the game, they would be unable to unless your life was at 5 or you controlled a creature.

There is no time between announcing that you want to cast a spell and paying for the spell costs.*

This is also the reason why if you cast Final Payment and while it is on the stack you cast the expansion side of Expansion // Explosion you would copy Final Payment without having to pay the additional cost, this is because the card is already on the stack and all casting costs have been met, and copying it is the same as copying any other such spells.

This is the same for any other copy effects.

*There is a window of time there, to activate mana abilities, this is what allows you to use Llanowar elves ability without having to do it before announcing that you want to cast the spell and to tap lands. This is usually disregarded as nothing can be done in this time, but there was a deck that abused this fact in modern not to long ago so I thought I'd mention it.