Teferi's Market

Teferi's Market enters the battlefield tapped with three bargain counters on it.
{t}, Remove a bargain counter from Teferi's Market: Add {u} to your mana pool
{5}{u}{u}, {t}, Remove a bargain counter from Teferi's Market: Take an extra turn after this one. Teferi's market doesn't untap during your next untap step. Activate this ability only as a sorcery.