The mana value of an object with no mana cost is 0, unless that object is the back face of a nonmodal double-faced permanent or spell, or it is a melded permanent.
April 22, 2021 · Strixhaven
The mana value of an object with no mana cost is 0, unless that object is the back face of a transforming double-faced permanent or is a melded permanent.
September 25, 2020 · Zendikar Rising
The converted mana cost of an object with no mana cost is 0, unless that object is the back face of a transforming double-faced permanent or is a melded permanent.
July 22, 2016 · Eldritch Moon
The converted mana cost of an object with no mana cost is 0, unless that object is the back face of a double-faced permanent or is a melded permanent.
April 8, 2016 · Shadows over Innistrad
The converted mana cost of an object with no mana cost is 0, unless that object is the back face of a double-faced permanent.
February 1, 2010 · Worldwake
The converted mana cost of an object with no mana cost is 0.