OH, oh, oh, this is my FAVORITE subject to teach! I have tons and tons of stuff, I’ll try not to deluge you. If you want to keep it to a half-credit, I think my favorite option would be the terrific Lessons for the Young Economist by Robert Murphy. There is both a text for students and a teacher guide; you can purchase them OR download them to a device for free (www.mises.org) Some video, like the Stossel videos, would be a great addition. (I love the Stossel videos, but they do not in themselves cover a complete course in economics. They are more like topic-driven. For basic theory you need more.) Have you yet had your student read the Uncle Eric books? Those are fun; there are ones covering economics and ones that are more personal finance, plus more. We LOVE the Free Market Reader as well–there are some very thought-provoking essays in there, some designed just for kids. We have a number of economics courses from The Teaching Company as well; we particularly like the ones by Timothy Taylor, although he is much more mainstream and we are fervent Austrians. Watch out there for the Peter Rodriguqez ones–he’s a Keynesian (sigh).
I also have and definitely recommend Bettina Bien Greaves’ wonderful Free Market Economics: A Reader and Free Market Economics: A Syllabus. Henry Hazlitt’s Economics in One Lesson is terrific, a modern classic, and Russell Roberts has a trio of “living books” that teach economic principles that are a TERRIFIC go-along and fun to boot. They are The Invisible Heart, The Choice, and The Price of Everything. I HIGHLY recommend these. I think Sonlight uses this.
I also subscribe to content from the Mises Foundation, the Foundation for Economic Education, and the Cato Instutite and send my kids 3-4 articles and essays a week showing various economic principles. The stuff at FEE is especially suited to younger kids, the articles are often very easy to read and entertaining too; Cato is more tied to current policy and current events, and Mises is very theoretical and deep.
Thomas Sowell has two really good economics books out there. Thinkwell has good courses, but very mainstream in approach. And there is an excellent product called Economics in a Box. I know some of the people who worked on this and it is top-notch, and one semester. Here is the link: http://www.economicsinabox.com/ CurrClick Live offers an economics class but I do not know what it is like.
Last and least, I am considering doing some type of course next year online, I’d be “testing out” and doing it for free the first time, if I can find a platform I could use that wouldn’t cost me much. It would definitely be free-market and Austrian in orientation, if that matters.
Good luck, this is a HUGELY important topic.