Madagascar which produce the best quality vanilla pods possible. Why so expensive? Because the flowers have to be artificially hand-pollinated and then once ripened, the fruits also have to be hand-picked. This is a labor intensive process that requires daily harvesting. Pure vanilla extract costs approximately USD $2-$3 per fluid ounce in international markets.

Vanilla is a flavoring derived from orchids of the genus Vanilla, primarily from the Mexican species, flat-leaved vanilla

Vanilla is the second-most expensive spice after saffron, because growing the vanilla seed pods is labor-intensive. Despite the expense, vanilla is highly valued for its flavor. As a result, vanilla is widely used in both commercial and domestic baking, perfume manufacture, and aromatherapy.

According to luxury-insider.com