Finale of Devastation (by itself) is currently selling at its cheapest for over $49.99 (it's sitting around $51 on TCGPlayer), and that's more than the retail price for the seven cards listed
Millennium Decks utilize The Unstoppable Exodia Incarnate for its strategy, but Exodia, the Legendary Defender isn't a bad alternative
Four generic mana is a great investment for whats normally an effect thatll cost you white mana (see: Grand Abolisher, Voice of Victory, etc.)
You can shoot Stuffy Doll as well, if you want to hit a player instead of a creature
#5 I think the Alcremie sleeves/deck box restored my faith in humanity #6 Can we all agree that the Dragon types sleeves are one of the coolest, like, ever?
So if you're here looking for a beginner recommendation I've got you covered