Remove Curse [Academy Priestess]

[iNano78]

  If there is a valid curse to remove, then [mwcard=MW1Q24] Ring of Asyra[/mwcard] gives a discount on the reveal; if not, you get 2 mana anyway

If it's casting cost is the same as Purify (0) then it can't benefit from Ring of Asyra or Arcane Ring. Nowhere in the card's text is X defined.

X implies it is variable, since no where is X defined as 0 either.  Has a ruling been made that Purify's casting cost is actually 0 and not equal to the amount described in the card text? 

I recall something about how a casting cost cannot be reduced below 0; e.g. if X = 0, you cannot have Ring of Asyra bring it to -1 and actually gain mana when casting Purify.  But I don't recall a ruling that said that X is always 0 for Purify, and thus that Asyra's Ring cannot reduce the casting cost to X-1 for X > 0. 

Is the argument that a card's text only applies when the spell is resolved, which is after the costs for the spell are paid, and thus X cannot depend on the card text? If so, this would bring up questions regarding any spell with casting cost X (or 2X, etc).  Or is it that X is simply not defined explicitly on either Purify or Remove Curse?  In that case, wouldn't it be simpler to errata the card text to explicitly state "X = sum of the mana costs of spells and removal costs of tokens removed this way" or something like that?

[Kaarin]

In Purify casting cost topic I linked in first post it's stated that Purify's cost should be 0, not X.

Purify calculates it's cost when it resolves. In this case the X is just there to remind you that the spell could have a variable cost. In this way it also interacts correctly with Enchantment transfusion.

The important thing here, Mystery, is you don't choose what you remove until the resolve spell step AND you don't have to pay anything until the resolve spell step. You pay for the effect of removing the poison, not for Purify itself. The casting cost of purify is essentially 0.

Thus, if they move things around before the Resolve Spell step, you don't have to pay any mana at all. You're still out the spell and the action, but you don't ever lose mana unnecessarily. If they let you get to the point where you're spending mana, the Resolve Spell step, then they are too late to stop it from having the intended effect and you will remove things exactly as you planned.

[Kelanen]

Has a ruling been made that Purify's casting cost is actually 0 and not equal to the amount described in the card text? 

Yep.

Purify (and most cards with an X - see Stranglevine) don't mean remotely what is written on them.

As per Aaron's ruling, Purify does not have a cost of X, it costs zero, with X additional mana paid on resolution.

I can't imagine Remove Curse is intended to work differently, but if so, it's galling that they wrote X again, not 0.