Cartoonish Digital Illustrations Needed

Hey! I am a book publisher, I am searching for an illustrator who can make a cover for me! It is a simple work, you will need to draw a teenager. So its Introduction to Microeconomics book for teenagers(this time). I will attach the first edition of book which was for kids only, now its next age group so we need a little realistic, engaging and rich drawing of a grown girl Elle studying in College with an old piggy bank. I have attached examples, my ideas. I am willing to pay $20.