Valdosta State University offers their 54-credit Doctor of Public Administration (DPA) program for online students at a tuition rate of $255/credit hour. That's a fantastic value, well below what many graduate or even some undergraduate programs charge for tuition.
The DPA program has been around since 2007, and the residency requirements are 2-day visits (Friday-Saturday) in the spring & fall semesters. Every matriculating class is held to a maximum size of 25 students though, so interested applicants should definitely put their best foot forward!