I'm in a similar position as you except I've not received any acceptance letters yet... still waiting and hoping. I applied to all PhD programs (might've been a little ambitious) and I've been told that sometimes applicants who apply to PhD programs will be accepted into MA programs w/out funding. If that happens to me, I'm prepared to pay my own way through my MA in hopes of receiving full funding to the PhD upon completing the MA program. After all, my career goals depend heavily on grad school, so any yes is, at least imo, an open door to success.
On that note, I'm not sure self paying for one or two grad level courses will really be worth your while, unless you happen to know that a specific teacher is teaching a course that would help you in your research proposal. Otherwise you're just paying ridiculous fees to pass the time. btw, you'll still have to apply to the school as a non-degree seeking student and be admitted.
just my own thoughts on the matter.