UHH YAH. NO!?! Why can't i say it!?!?

I keep my younger brother's cologne so he won't misuse it. My grandfather liked the scent so he asked my if i can give it to him! I obviously didnt want to because the cologne my mother bought for him is between 80-100 the last time i check it. I told him that all of my perfumes are for girl (trying to say that i don't know which cologne/perfume he is mentioning) He states "Oh i don't care if its for boys or girls I just need to to go on vacation and use" I dont want to be rude by how do I say no?!? My grandpa doesn't get the point as says "Oh its fine I'll ask your mom to take the one you have and give it to me" I was astounded and had no comment. I like my perfume and i don't want to give him $100 worth! I told him it was expensive and he said "I don't have any more" (Even though he gets 800$ every month from babysitting us, his grandkids.