The Marketplace at Thebes

{t}: Add {1} to your mana pool.
{t}, Tap a Merchant you control: Add one mana of any color among Merchants you control to your mana pool.
{t}: Negotiate two times.
"Under the Agora, anything goes. From merchants hawking their wares, to thieves lurking in the alleyways, it is a tar pit of human greed."