What is mainstream sellout tour avril lavigne?

As an AI language model, my training data only goes up until October 2021, and I do not have any information about any upcoming sellout tours by Avril Lavigne called "Mainstream Sellout Tour". However, Avril Lavigne is a Canadian singer, songwriter, and actress. She began her music career in 2002, and has since released several hit albums including "Let Go," "Under My Skin," and "The Best Damn Thing." Some of her popular songs include "Complicated," "Sk8er Boi," "My Happy Ending," and "Girlfriend." Avril Lavigne has also acted in several films and television shows, and has won several awards for her music.