Here are some resoures on the web that may help students learn about gains from trade.

1. Watch the Economic Detective on comparative advantage and trade (2:31).
2. Watch this video describing the hockey stick of economic prosperity (4:54)
3. Watch Khan on comparative advantage and trade (8:55)
4. Optional: Visit this post to see 4 videos and 2 articles that present different opinions of whether free trade is good or bad. One article distinguishes between free trade and fair trade.