The Federal Reserve

{t}: Add {x} mana in any combination of
colors.
{1},{t}: Players can't cast spells that have a
mana cost of {x} or less until your next
upkeep.
{3}{x}{x},{t}: Search your library for a card that
has a mana cost of {x}{x} or less. You may cast
that card this turn without paying its mana cost