Here's one good source - LSU.
LSU Continuing Education Campus is closed till tomorrow (Hurricane Isaac) so I can't see course listings till then, but I'm almost positive you can get 2 3-credit accounting courses. You'll know Friday, I guess. Least expensive RA 4-year school credits I know of. Last I looked, 3-credit courses were around $240+ - that's $80 a credit-hour.
Straighterline - you'd get your 6 credits when they're transferred to one of their partner colleges. At least, so says the website. LSU - you get them right away, naturally. And no, you don't have to be enrolled in a degree program with LSU. In fact, (sadly) they don't offer enough distance courses to complete
any particular degree that way. At those prices, many wish they did. Great school.
A second low-cost way might be Penn Foster College
http://www.pennfoster.edu . The school is Nationally Accredited (DETC) not RA - but the courses are pretty well all ACE-reviewed, which means they should be considered OK for transfer to RA. If your employer will accept this type of accreditation, with ACE-reviewed courses, this would be a low-cost source. Penn Foster will usually sell their courses singly, without enrolment in a degree program -- and I think it works out to around $80 a credit.
Distance study through a community college (RA) is available. One of the most popular is here:
http://www.clovis.edu. Again, good school - and its popularity is due in part to its low cost per credit.
Another alternative might be - a Community college near you. "In-State" tuition can be astonishingly low, some places. I hear it's under $40 a credit in some states - and of course we're talking RA. I've done those six credits you're looking for -- I did 'em here, at a Canadian community college. And I can tell you -- as long as the school has proper accreditation - let
price be your guide. Nothing else. What you'll learn is pretty much the same -- anywhere you take it. I wish you every success. You'll do well, I'm sure.
Johann