There aren't very many. Check out MS Applied Economics at UND - they offer Macro but I don't know if you can take just one class. Master of Science in Applied Economics (MSAE) | Online & Distance Education Threads here: http://www.degreeinfo.com/general-distance-learning-discussions/32503-ms-economics.html http://www.degreeinfo.com/business-mba-degrees/40250-update-ms-applied-economics-und.html
Also, check out the MS in Applied Econ at Johns Hopkins University. You can take the classes as a non-degree student, if you wish. Johns Hopkins University | Advanced Academic Programs | Krieger School of Arts and Sciences | Academic Programs | Applied Economics | Home They are a little under $3,200 per class, though
Check out Georgia Southern. They offer the course, but I don't know the details. The program is AACSB. Master of Science in Applied Economics - GSU