Unless you use most of the charge during the same day, it is quite doable.
Sure the charge is slow, but you can plug it in the evening and let it charge during the night, like you'd do for a smartphone.
Depending on the capacity you may not get a full charge, but it is enough for most uses. If it charges enough for what you'll do during the day, it isn't a problem at all.
You could repurpose an old workstation, bought dirt cheap on eBay if you are lucky, but even then you'll have to get yourself an HDD, maybe multiple of them if you want to have data redundancy.
For anything new your best bet is a 2 bay ready made NAS, but you'll have to invest around 300€ for the cheapest one.
Yeah, for that price you won't find anything new. For illustration, when I bought a new Athlon 3000G, which was the very lower CPU on their AM4 offering, it was at 55€ without anything else.
Unfortunately it isn't always as easy as that. Depending on what broke on the old computer, finding the right replacement part may be a nightmare.
You can often find old CPUs on eBay for dirt cheap, but the catch is that there are close to no motherboards available, and the ones that are are way too expensive to be interesting.
Moreover, it isn't always interesting to run old hardware for something that is on 24/7. My R5900X NAS sips 75W... At idle. 130W at full power. Depending on your electricity price, it could be more interesting to buy newer, more efficient hardware, than using older ones.
The article says nothing about what OP implies. The only thing it says is that he died from a heart attack following "injuries received in a biker bar brawl during a night out in Monterey, California."
Is there a c/lostlemming somewhere?