An 'expensive' smelling fragrance is usually less about one particular ingredient and more about balance. Scents often feel more sophisticated when they have contrast, depth, and a clear structure instead of one note dominating everything.
For example, sweetness can feel richer when paired with woods, spice, resinous notes, or something fresh. A floral can feel more dimensional with green, musky, or citrus elements around it. Complexity does not have to mean heaviness, though. A clean fragrance can feel polished when its notes work together naturally. Price alone does not determine how luxurious a scent will seem to your nose.
'Expensive' is also a personal association. Someone may connect a polished woody scent with a favorite hotel, while someone else finds a soft floral more luxurious. A familiar memory can influence the impression as much as the number of notes listed.
When shopping, look for descriptions of the balance you enjoy: dry rather than syrupy, softly musky rather than powdery, or warm with a little brightness. You do not need a complicated note list or maximum intensity. A fragrance that sits comfortably in the room and remains pleasant after the first impression can feel more considered than one that overwhelms the space.