The key to spice trade is TINA - There is no alternative - in financial terms. The largest form of investment in Middle Ages had been farmland with average ROI

The key to spice trade is TINA - There is no alternative - in financial terms. The largest form of investment in Middle Ages had been farmland with average ROI of c.a. 7-8 percent but no guarantee (wars, diseases, crop failure). The ROI of spice trade was 200-300 percent over similar period. So if you wanted double you capital it was either spice trade or investing in land for 20 years. And the cost? It is like asking Citadel about their servers costs....