[+1]: Scry 1. You may tap an untapped artifact you control. If you do, draw a card.
[−2]: Create two 1/1 colorless Thopter artifact creature tokens with flying. They gain haste until end of turn.
[−4]: You get an emblem with "Artifact creatures you control get +1/+1" and "Artifact spells you cast cost {1} less to cast."
For the first ability, you don't choose which artifact to tap until the ability resolves.
If you manage to activate Saheeli's last ability multiple times, each emblem you get is applied independently. For example, if you have two of those emblems, artifact creatures you control get +2/+2 and artifact spells you cast cost {2} less.
The cost reduction provided by Saheeli's emblem can never reduce the colored mana costs of an artifact spell.