You could enroll at Excelsior College http://www.excelsior.edu and then take classes wherever and whenever you could find them cheapest.

Excelsior will accept nearly 100% of the degree requirements in transfer but their own courses are expensive. The cheapest course providers don’t have the degree you need.

By combining the two, you’d get out least expensive and have a viable regionally accredited degree.

Some providers of inexpensive classes online are Brigham Young University and Louisiana State University. Several community colleges offer courses online very cheap but these will only meet your lower level requirements.

You could also consider testing out of some courses to save time and expense. Excelsior accepts CLEP/DANTES/AP/IP etc. as well as their own exams in many subjects.