Cube designed for a new format inspired by Star Realms. STILL IN PROGRESS

Run-down of the rules: Players begin with a deck consisting of 1 land of every color. If your library is empty, you shuffle your graveyard into your library (if theres still no library, you lose) and then draw. The cube is used to replenish a trade row of 5 cards. During your turn you can pay mana to "buy" a card off the trade row and place it into your graveyard. Cards cost twice their rank of rarity, by this I mean common costs 2, uncommon costs 4, rare costs 6, mythic costs 8. You can also pay 2 mana to wipe the trade row to get a fresh 5 cards, or to "buy" a land of any color. Beyond that, it's magic played as normal.