When getting my students to consider whether international trade is beneficial or not I always get them to think and write about what their life would be like with and without international trade.
These are the basic instructions that I give them:
“Start in the morning of a normal day and work through to bedtime. Brainstorm all the ways trade affects your day. (Takes about 15 min)
Once you have written your day. Go through the list and try and find things you do which don’t depend on trade. (About 5 min)
Now spend 10 min. commenting on whether you think trade enhances or detracts from your life.”
I encourage them to think specifically for the first two bits and then more broadly on the last question.
Just because I quite enjoy doing this exercise my life with trade is here:
They tend to really enjoy doing this and you can get some really good evaluation discussion going based around what they write.