Algorism outpaced the abacus for a reason, and the slide rule outpaced algorism for a reason as well, but they’re all good skills to have some practice with. Have you ever had to do long division on an abacus? It ain’t pretty.

Buy used, compensate for the loss in power with algorithmic ingenuity, yadda yadda.

Also, if you can do the thing the app does on paper, you should just do it on paper and can save the computer for more difficult tasks like the old-timers that paved the way for our modern-day laziness.

Use the public library, also.

I dunno, man. Seems like all the convenient options at this point require you to capitulate to some asshole trying to jack up prices and deny payouts, and the only option now is to take high roads that are unpaved.