Oswald Fiddlebender
Legendary Creature — Gnome Artificer
Magical Tinkering — , 
, Sacrifice an artifact: Search your library for an artifact card with mana value equal to 1 plus the sacrificed artifact's mana value, put it onto the battlefield, then shuffle. Activate only as a sorcery.
"Can't see this airship crashing in the near future. Sturdy as a rock."
Steven Belledin
Rulings
An artifact's mana value is determined solely by the mana symbols printed in its upper right corner (unless that artifact is copying something else; see below). If its mana cost includes {X}, X is considered to be 0. If it has no mana symbols in its upper right corner (because it's an animated land that's also an artifact, for example), its mana value is 0. Ignore any alternative costs or additional costs (such as kicker) paid when the artifact spell was cast.
(wotc • 2021-07-23)
A token has a mana value of 0 unless it's copying something else.
(wotc • 2021-07-23)
If an artifact is copying something else, its mana value is the mana value of whatever it's copying.
(wotc • 2021-07-23)
Printings
Rulings
An artifact's mana value is determined solely by the mana symbols printed in its upper right corner (unless that artifact is copying something else; see below). If its mana cost includes {X}, X is considered to be 0. If it has no mana symbols in its upper right corner (because it's an animated land that's also an artifact, for example), its mana value is 0. Ignore any alternative costs or additional costs (such as kicker) paid when the artifact spell was cast.
(wotc • 2021-07-23)
A token has a mana value of 0 unless it's copying something else.
(wotc • 2021-07-23)
If an artifact is copying something else, its mana value is the mana value of whatever it's copying.
(wotc • 2021-07-23)