I think she was trying to teach him humility by going to Goodwill. I would also make him volunteer at a food bank or serve dinner on Thanksgiving at a church. A 13 year old who makes fun of poor people is heading in the wrong direction.
No internet.
Walk to school.
Eat rice and beans.
Mow a older neighbor’s lawn for free.
YEARS ago in San Diego, I used to hit the Goodwill stores for old books, and got some interesting reading (US Army experience in 1900s Philippines).
My youngest was about that age and as we walked back to the car, he made some disparaging remarks about the people he saw there. I told him we were down there on a lark and could always go back to a nice home - these people were STUCK there and had little choice. It seemed to sink in as he never again mocked those who were less fortunate than us.