One of the subjects I have been researching recently is Jasmine.  It's pretty interesting - and one of the things that I was not generally aware of is that certain crops are really expensive because of the amount of manual labour involved.   Jasmine is one - because the process of the extraction of the essential oil is complex.   The most expensive crops of all are said to be Saffron (because the stamens are so minute it takes a field of the stuff to make a pound of Saffron) and vanilla (due to the complexity of the curing process).
Many of the ingredients in perfumery involve the collection of oil from flower petals - Jasmine being one and Rose being another.   Rose too needs a mountain of petals in order to make the essential oil - hence the expense.
Most people don't realise that a lot of modern perfumes contain complex blends of essential oils that have been in use in perfumery for hundreds of years.   Their alluring effect is time-tested, you might say...

(a chapter from a book I am writing)