Prices depended, of course, on supply and demand, and these changed significantly over the history of the spice trade, which goes back at least to the ancient Romans. Whenever a spice trade question comes up, I direct people to start with Krondl's "The Taste of Conquest" because it is an excellent broad treatment of the Venetian, Portuguese, and Dutch phases of the trade that is both interesting and informative.

The big money-maker throughout the history of the trade (and indeed still today for Indian spice planters, according to Krondl) was black pepper, but this has much to do with not just the price but also the fact that it was usually traded in much larger quantities than the other oriental spices, which doesn't quite answer your question, since you seem interested in "per pound." Clove, nutmeg, and mace were often significantly more expensive (and sold in much smaller quantities) because these came from even further east and were thus harder to get control of. One of the narratives Krondl includes is the brutal methods (amounting essentially to genocide of the populations of certain islands) employed by the VOC (Dutch East India Company) to establish a monopoly over nutmeg and mace, which come from the same plant and historically had a small range over which they were grown, which allowed the VOC to more or less dictate prices.