It may be possible to find discontinued perfumes on large retail websites like Amazon or auction sites like eBay. For people who can travel out of the country, finding discontinued brands overseas is possible as fragrances discontinued in the United States may still be sold in other countries.
Online retailers like Amazon may take a while to deplete a stock of discontinued perfume, making it available for months after production ceases. The best time to stockpile a favorite brand is shortly before it becomes discontinued. Most brands will make an announcement before discontinuing a fragrance, making it easier to stockpile a favorite scent.