I think
@periogirl28 nailed it. While this thread is always interesting to read, it's all anecdotal. So you can't draw any specific conclusions from other spending patterns, because it depends on so many variables, some of which you can control, some of which you can't. Healthy spending is always going to help, but beyond that, it depends on what your store gets in, how competitive it is, how you vibe with your SA, how much pull your SA has, how often you stop by, etc.
All of that to say, I wouldn't really worry about specific item breakdown. Just buy what you enjoy and want/need.
A MK is for sure going to be a competitive bag. I just got one as a second QB (although my SA did get me a SO slot a few months ago between the first and second), but I also got a C a few months ago as well. Because of that, I think it becomes difficult to put any precision on the total spend that I had to get the MK itself. In other words, it's not an exact science, and more of a 'go with the flow'.