Many people collect perfumes and colognes. So it is not surprising that they are big sellers online. For example check out a recent sale on Ebay.

Vintage Christian Dior Cologne Miss Dior 4 FL.Oz. Original Box Unopened

A quick look at Etsy showed this

Vintage Rare Womens Lauren Ralph Lauren COLOGNE Eau de Toilette 4 oz

Now, here is an interesting article on the popularity of perfume bottles for resell value..

Here is a video by a perfume and cologne collector