How much is card advantage worth? (A question no answer yet.)

[OldTrees]

Just as the topic says. How much is card advantage worth?

If we had 2 Blessings combined into one card +6|+6 what should this cost?
Obviously it is better than 2 Blessings 6 |4 but how much better?

2 Novas are about equivalent to a Supernova (with the Supernova costing 2 more)
Since many upgraded creatures get a -1 or -2 cost reduction does this mean that the card advantage Supernova gives is worth 3-4 ?.

[Glitch]

Well, think of it this way.

I do with one card what you do with to.  The advantage, clearly, is in the value of my other card.

[OldTrees]

Well, think of it this way.

I do with one card what you do with to.  The advantage, clearly, is in the value of my other card.

But you pay for that other card with its casting cost. So the benefit is the ability to play the other card. How much is the ability to play another card worth?

I am looking to quantify the value of card advantage as a function of something.

[Rooftrellen]

Hmm, there are different kind of card advantages.

At first, I thought, what cost would I pay for that blessing if I could add a "draw a card" to it.  But that is quite different.  There would be a lower limit to the bonus than a 2x blessing card, and chances are good that you would get a different card all together, not another blessing to match.

How much the card would be worth, if it were twice as good as an existing card with established cost, I would say is dependent upon the exact effect.

If you gave me a stopwatch permanent, which allowed me to draw 2 cards upgraded, I don't think I would pay more than 2 time quanta for it.  Adding another hourglass wouldn't be worth a single quanta extra.

I would probably be willing to pay 10 for a cataclysm spell that destroyed 6 pillars, though.  The ability to pack that much power into a single card would be worth a lot to me.

I would probably pay 150% more for a FFQ that produced 2 fireflies, both for initial cost and firefly creation.

There are two questions.  How much less advantage would you get from simply adding a second of the same card, compared to using a 2x card.  I don't think that using an extra copy if some cards would really be trouble.  Others, the extra power from a single cast could be amazing, in addition to saving a space for another card.  Really, how much would it be worth to be healed for double your max HP minus 2?  The card advantage isn't the only thing to consider for a card like that.  A card that draws extra cards may be worth having more common, rather than more powerful, rather than space saved being a real issue.

The second is how long can the card be used?  It will always be nice to boost a creature, but drawing extra cards or creating extra quanta won't be useful later in the game.  A card like graveyard, if it were to produce 2 skeletons, would be worth something, but given that skeletons won't be doing much against most shields, it falls in the middle of the road, could be useful all game, or they could get out an ice shield 2nd turn and it would be nearly/totally useless the rest of the game.

I don't think there is a good way to measure what a cardx2 would be worth.

The eyeball test will have to do the trick, I think.