Natalie Maines. 2013 photo by Ashley Landis for American-Statesman

To benefit the social activism nonprofit Proclaim Justice, Dixie Chicks singer is auctioning off two tickets to Sunday’s sold-out Dixie Chicks concert at Austin360 Amphitheater that include VIP and meet-and-greet access.

According to its website, Proclaim Justice “is dedicated to winning freedom for inmates who are factually innocent of the crimes for which they were convicted.”

Bids can be submitted online; as of late Wednesday afternoon, the price was at $500. The auction ends Wednesday afternoon.