Even though Goodwill is a "non-profit", it's current leadership is out to make as much money as feasible. This isn't to be taken as a dastardly thing, it is business after all, but this is where online auctions and opening game stores is coming from.
Still seems wrong that they would charge high prices for anything when it's all given to them with the intent of helping people out.
The people they are helping out the most are their employees that are making better than minimum wage, participating in tuition re-imbursement programs, and getting better benefits than they would at some of the larger chain stores.