Saffron (30 denarii)

You point to a tiny bottle on a shelf behind the merchant. "That," you say. "That's saffron, isn't it?"

The merchant flashes you a grin. "That it is. A fine product from the distant east! Expensive, but just a few strands of it will bring both flavor and color to the otherwise simple dishes of this city."

You smile. "Excellent. I'll take that bottle."

"Thirty denarii," he says smoothly as he retrieves the bottle. Seeing your expression, he shrugs and says, "Well, it has come a long way and is hard to grow! You'd best be careful with it."

Grumbling slightly, you pass over the coins and tuck the bottle safely into your pouch.