Is there any one class I should take as a current student and hopeful transactional attorney?

I grew up poor, and am pretty financially illiterate. Never took a business class or anything close in undegrad. I barely know what a stock is (and I am probably wrong).

Despite that (perhaps because of that), I hope to become a transactional Big Law attorney, and given my grades and school have at least an ok shot at it.

I have heard (and I believe) that 99% of what you learn in law school will not matter for your legal job. However, is there a class that might be helpful just for understanding basic business/finance background things anyone would recommend?

Things like secured transactions, business associations, federal income tax or anything else? My school does offer a sort of "business introduction for lawyers class" I plan on taking, but won't be available until spirng 2023.

Any advice would be appreciated.