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- Urza's Saga is a land, so it can only be played as a land. It cannot be cast as a spell.
- Even though Urza's Saga is a land, it is also still a Saga, and it will be sacrificed after its last chapter ability resolves.
- Urza's Saga gains an ability from its first and second chapters. It keeps those abilities for as long as it's on the battlefield.
- While resolving the chapter III ability, you can find only a card with actual mana cost {0} or {1}, not mana value 0 or 1. For example, you couldn't find a card with mana cost {U} or one with mana cost {X}.
- If Urza's Saga loses all of its chapter abilities but is still a Saga, perhaps due to a card like Blood Moon, it will immediately be sacrificed.
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The way the card is worded it can only tutor for artifacts with an actual mana cost of generic 0 or 1, which is different from mana value 0 or 1 (!). So, no lands, no cards with no mana cost (like "Lotus Bloom"), nothing with X in the cost and nothing with non-generic mana requirements (like colored mana).
It costs a land drop but goes away quickly.
The Constructs cost 3 mana each.