I work in Matlab, is not free but home use is not cost prohibitive if you look at the licenses as an expense for a hobby and a way to learn new stuff. There are lots of premade toolboxes available. I have not used R but have heard good things about it. I have tried a few of the free alternatives to Matlab and found them lacking - just did not have the polish or ease of use I wanted. With a programming language there will be a good learning curve depending on your background.
Oof I wouldn't ever purchase a home license for matlab unless it was required for a personal business.
I've used R for some personal finances (ggplots, summary stats). Of the languages I have experience in, if one knows basic, R, matlab or python the learning curve is shallow.
edit: Just to be helpful to OP, I will +1 portfoliocharts. It's visually sexy