Mycosynth Golem
Artifact Creature — Golem
Affinity for artifacts (This spell costs 
less to cast for each artifact you control.)
Artifact creature spells you cast have affinity for artifacts. (They cost less to cast for each artifact you control.)
Paolo Parente
Fifth Dawn (5DN)
• #137Rulings
The spells gain affinity for artifacts as they’re put onto the stack. They don’t have the ability while they’re cards in your hand.
(wotc • 2004-12-01)
Two or more instances of the affinity ability are cumulative, even if they’re both affinity for the same thing.
(wotc • 2004-12-01)
If Mycosynth Golem is sacrificed as part of the cost to cast a spell, the cost reduction will already be locked in, and the cost won’t be increased.
(wotc • 2004-12-01)
Rulings
The spells gain affinity for artifacts as they’re put onto the stack. They don’t have the ability while they’re cards in your hand.
(wotc • 2004-12-01)
Two or more instances of the affinity ability are cumulative, even if they’re both affinity for the same thing.
(wotc • 2004-12-01)
If Mycosynth Golem is sacrificed as part of the cost to cast a spell, the cost reduction will already be locked in, and the cost won’t be increased.
(wotc • 2004-12-01)