Whir of Invention 
Instant
Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pays for 
.)
Search your library for an artifact card with mana value X or less, put it onto the battlefield, then shuffle.
Legality
standardNOT LEGALpioneerLEGALmodernLEGALlegacyLEGALvintageLEGALcommanderLEGAL