I’m tempted to employ tom sawyer’s approach above…save the cakes, maybe wash a few times and re-use. Then spend a few bucks on new yeast when needed.
I recently racked a batch to secondary that I had put right on top of a used cake in the carboy for the first time…that seemed to work really well, and couldn’t be easier.
On a related note…I’ve read that using the same yeast much more than 4 times is risky for a variety of reasons…do others agree/disagree?
Also…If you took a single cake and washed and stored the yeast in multiple jars…could you not use the yeast from each jar 4 times…presuming that you make a starter each time and that generates a new cake…which you then split into multiple jars…etc, etc, etc…?