Hearthpwn

Thistle Tea is really the only 6 cost worth any time playing twice in a turn.

Does the copy retain the same card cost, or will it be free (0-mana)? This way, maybe you can't copy cards that are too costly.

It copies the initial mana cost.

Ie. If you play a Shadowstepped Jade Spirit that would cost 2 Mana, the copy from Shadow Reflection would still cost 4 Mana.

First of all it's way more consistent to check this interaction using Lorewalker Cho.
second my guess is the card will transform into a Dead Man's Hand before it goes into your deck, but we'll have to get our hands on the cards to make sure.

Mind Vision should work though.

Max 5 cost or 6 cost spell with Preparation (3+6 is still playable in 1 turn)

it is always funny going up against guys with this expensive hero card in their deck using a budget token druid and laughing as they mill their own deck or draw their weapon on a full hand.Also, you can't combine this with preperation for obvious reasons.

Well I meant:
Preparation into discount spell into same spell without discount, which will allow you to play 6 mana spell twice... Rogue doesn't really have 6 mana spells that you would want to play twice in the same turn, but possibility is there for future...

Prep into Sprint would work if anyone even really runs that anymore.