I don't think this is a good homework assignment. We want to work on his selection ability, not his bargain hunting ability. He needs to learn what doesn't. Restricting him to discounted stuff isn't going to do that. Now if he starts batting .750...then we can encourage him to look at eBay/Yoox/etc
Respectfully disagree. The purpose of this assignment is not to get him to purchase these finds.
The purpose is to raise his awareness that he need not always pay retail.