Grim Merchant

When Grim Trader enters the battlefield, you
may exile up to three instants and/or sorceries from your hand and put a stock counter on them. You get a number of gold counters equal to the total converted mana cost of the exiled cards.
{2}, Pay X gold counters: choose a spell with a stock counter on it with converted mana cost X. Copy it. You may cast the copy without paying its mana cost.