Welcome to the Sandbox
You have full use of the deck editor! However, as long as you remain in sandbox mode, you will be unable to save your changes.
To save this as a new deck,
Choose your preferred layout. You can change this at any time using the Deck filters / View as options above.
Spells you cast but don't own cost {1} less to cast. Whenever one or more creatures you control deal combat damage to a player, look at the top card of that player's library, then exile it face down. You may play that card for as long as it remains exiled, and mana of any type can be spent to cast that spell.