Birkin bag is developed on the basis of Kelly bag, and with a larger size and without the cover; Birkin is perfect for trips and serves as briefcase. What’s more, Birkin has a more casual style than Kelly and a richer choice of materials and colors as well. Turns out that, according to Wikipedia, Jane Birkin herself had to pay for the now famous Hermes bag that was first made for her. Cheap french! She was later reimbursed with a 10% discount on all Hermes products.