Accordig to the rule 702.36c, to cast a card using its morph ability, turn it face down. It becomes a 2/2 face-down creature card with no text, no name, no subtypes, and no mana cost. Any effects or prohibitions that would apply to casting a card with these characteristics (and not the face-up card’s characteristics) are applied to casting this card.
With Bolas's Citadel in play, Can i pay 0 to cast a morph card from top of library?
Not in this case, no. Both the cost from the Citadel and Morph are alternate costs and you can only use 1 alternate cost when casting a spell. And, in this case, only one cost lets you cast it from the top of your library.
Not in this case, no. Both the cost from the Citadel and Morph are alternate costs and you can only use 1 alternate cost when casting a spell. And, in this case, only one cost lets you cast it from the top of your library.
You can cast Visions off Citadel because it gives you a payable cost; you are not trying to use 2 alternate costs there. You are *only* using Citadel's cost to cast the Visions. It doesn't matter that Visions normally has an unpayable cost because you aren't paying that.
In the case of Morph, you are trying to use both the Morph cost (turn it face down, cast for 3) and Citadel (pay 0 life now that it is face down). And you can't combine alternate costs.
You can cast Visions off Citadel because it gives you a payable cost; you are not trying to use 2 alternate costs there. You are *only* using Citadel's cost to cast the Visions. It doesn't matter that Visions normally has an unpayable cost because you aren't paying that.
In the case of Morph, you are trying to use both the Morph cost (turn it face down, cast for 3) and Citadel (pay 0 life now that it is face down). And you can't combine alternate costs.
So in that case I would have to pay 3 life or can't cast using Citadel?
You can't cast the card face down at all with Citadel. As to the amount of life to pay, it depends on the CMC of the face-up card. Scornful Egotist will cost you 8 life while Birchlore Rangers will cost you 1 life. Morph or the cost to cast to face down, will not factor into anything with Citadel.
With Bolas's Citadel in play, Can i pay 0 to cast a morph card from top of library?
Okay, but Bolas's Citadel doesn't allow me to use Ancestral Vision for 0 life even though it has an alternative cost?
Why i can't use this same logic with morph?
In the case of Morph, you are trying to use both the Morph cost (turn it face down, cast for 3) and Citadel (pay 0 life now that it is face down). And you can't combine alternate costs.
So in that case I would have to pay 3 life or can't cast using Citadel?