If you are willing to pay, some of the courses and programs like micro masters, micro bachelors on edx can count for credit, which is not necessarily cheap, but may be cheaper than it otherwise might be [1], also see [2] as example.
All though even then, it may be cheaper to just enroll in some local or online classes at a community college in your state for a couple hundred dollars.
All though even then, it may be cheaper to just enroll in some local or online classes at a community college in your state for a couple hundred dollars.
[1] https://support.edx.org/hc/en-us/articles/206501438-Can-I-re...
[2] https://www.edx.org/masters/micromasters/purduex-nano-scienc...