Wizard's Spellbook

{t}: Exile target instant or sorcery card from
a graveyard. Roll a d20. Activate only as a sorcery.

1 -9 | Copy that card. You may cast the copy.
10 -19 | Copy that card. You may cast the copy
by paying {1} rather than paying its mana cost.
20 | Copy each card exiled with Wizard's Spell-
book. You may cast any number of the copies
without paying their mana costs.