Cheapest priced copy (War of the Spark): $20.99 at Card Kingdom, foil, near mint, their price list as of .
Tezzeret, Master of the Bridge 
Legendary Planeswalker — Tezzeret · Mythic · Secret Lair Drop · #1701
Creature and planeswalker spells you cast have affinity for artifacts. (They cost {1} less to cast for each artifact you control.)
+2: Tezzeret deals X damage to each opponent, where X is the number of artifacts you control. You gain X life.
−3: Return target artifact card from your graveyard to your hand.
−8: Exile the top ten cards of your library. Put all artifact cards from among them onto the battlefield.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
2 printings · $20.99 to $29.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Secret Lair Drop | 1701 | Mythic | $22.99 | $29.99 |
| War of the Spark | 275 | Mythic | — | $20.99 |
8 rulings from Wizards of the Coast
- 3 May 2019Affinity for artifacts means "This spell costs {1} less for each artifact you control."
- 3 May 2019In a Two-Headed Giant game, Tezzeret's first loyalty ability causes the opposing team to lose twice X life and you gain X life.
- 3 May 2019The cost reduction is set before you pay any of the spell's costs. Specifically, you could lock in a discount for an artifact you control and then sacrifice that artifact to activate a mana ability.
- 3 May 2019Affinity doesn't change the spell's mana value. It changes only how much mana you pay to cast the spell.
- 3 May 2019Affinity can reduce only generic mana in a spell's cost. It can't reduce color requirements.
- 3 May 2019If there are any additional costs or cost increases that would apply to a spell with affinity, apply those before applying any cost reductions.
- 3 May 2019If a spell has multiple instances of affinity, each applies.
- 3 May 2019Tezzeret himself doesn't have affinity for artifacts.