I cannot recommend highly enough the EconTalk conversation between Russ Roberts and Mike Munger on price gouging. Some hurricane, some gasoline, some John Locke, some Aquinas, well worth your time. Their discussion of Locke is fascinating. The comments from readers/listeners are also quite good.
On the same topic, Art Carden posts a useful infographic on price gouging. Good conversation starter/discussion focal point for students.