Hearthpwn

Cards that are changeable are: Sylvannas, Ragnaros, Lich king, Colossus of moon, and Yashraj

Id recommend opening classic packs to get Sylvannas, Tirion, and Ragnaros

But if you are too poor for these flashy legendary minions you can always make this a non-singleton deck and run multiples commons - epics. Some examples are: Deranged doctor, Sleepy dragon, Moshogg Enforcer etc. There are millions of cheap big minions in hearthstone so don't feel ashamed to use them and kick a** with this deck.

Also the cheap spells can be replaced with any other cheap spells, i just have epics in there because cool. Just remember the main cards u want in your starting hand are:

Nozdormu or call the adventure

Prismatic lense or Duel

Time out and Santuary

Shrinkray Consecration and Equality