Let me clarify first- I would never use CC music on a client paying a "normal" fee for a video, because you have to attribute the artist in the piece, and I wouldn't think someone paying good money would want attribution credits in their video.

However, when starting out and doing jobs for free or very low fee, does anyone think it would be appropriate to use? I just finished editing a 2-hour long-form for my first paying client but I would spend a significant chunk of my profit from this gig just on licensing music. I know better than to simply rip music off, but don't want my profit to completely dissapear. Should I just "suck it up"?

Yes, often. Why wouldn't you? Much of it is as good or better than commercial music. Check with your clients: I suggest they wouldn't mind attribution credits at all.

Most everything you watch will have some type of credit give for music (or where the license was obtained). I see no problem with using it. I imagine clients will not mind as well.