Laura, so I don't miss anything, I'm putting my answers after each of your questions here, in blue.
Also be sure to check both AAPC and AHIMA's sites for additional information. That is where I found the answers I've listed below for you, although if I misunderstood anything, I'm sure one of our graduates or instructors will correct me!
Does anyone know how many CE credits are required for both the CPC and CCS?
The CPC credential requires 36 credits every 2 years. The CCS credential requires 20 credits every two years, 10 of which come from two required annual reviews. Credential requirements may change if you also have other credentials from the given organization in addition to the CPC or CCS.
Is it different for each state?
Both credentials are national, and the requirements do not vary by state.
Can credits overlap between certificates? Is it yearly or every 3 years?
CEUs do not carry over - for instance, if you have 38 credits for the CPC as of your recertification date, the extra two will not be applied to the next recertification cycle. Both AHIMA and AAPC use a 2-year cycle.
Do you sign up and pay yourself for courses or do employers oversee this?
That depends on the employer. Some will pay for continuing education, others may provide it directly, but it's best to plan on having to obtain it yourself. Both AAPC and AHIMA have free CEU options available, so you don't necessarily need to purchase anything.