How many books should I collect to start a store?

I want to open a bookstore specifically selling antique and rare books. I have lots of great ideas and I know once a used bookstore of any kind is opened they collect books VERY quickly. However, how many should I start with? I don't want it to be completely ridiculous with like, 10 books on a shelf. Although I don't want to have to fill my entire home with trillions of valuable, very delicate books for years before I can get started, either. A little help with a general amount to open with? Thank you so much :)