You would need their permission if any of the following circumstances exist:1) When you buy the perfume, there are "terms of sale" (e.g. on the box, in an insert, on the company's website if you buy online, etc.) stating "not for resale." If so, then you purchase it subject to an agreement to not resell, and if you do resell, you are in breach of contract.2) When you repackage or resell it, you use their logos, trademarks, copyrighted material, etc.--you cannot use any of that to market, etc. your product without their permission, since they have the sole right to determine or allow use of their intellectual property.3) If you in some way suggest a connection between you and the perfume company (such as that you are a distributor or agent of theirs)--that is a violation of some intellectual property and marketing laws.