If there arent two appropriate cards to choose, choose whichever you can and that player discards that card
Its easily #1, and arguably among the best activated ability commanders in the game, but only because its so broken and easy to turn into a one-card infinite combo that starts the game in your command zone
If you're running an artifact deck, a Foundry Inspector or equivalent cost reducer will bring the mana cost of the first card you draw from it in line with (an undiscounted) The One Ring
A single green mana to activate this ability is nothing, too, so this has the potential to go up if enough EDH players want to cheat stuff in
Now I feel like a lot of the acceleration needs to come in the form of actual lands on the battlefield, so cards like Nissa, Vastwood Seer and Shrine of the Forsaken Gods hit their critical seven land point