Sara Blakely was selling fax machines door-to-door when she had the idea for Spanx. With no background in fashion, she faced rejection after rejection from manufacturers who laughed at her concept. She persisted, refined her prototype, and finally found a supportive manufacturer. Spanx launched and became an overnight sensation, making Blakely the youngest self-made female billionaire. Her story proves that determination, creativity, and belief in yourself can turn a simple idea into a life-changing product.