You don't get support and the laptop can fail on you on week 4 you're just SOL.
I understand the value of second hand, and randomly bought a discarded corporate HP tower for my home server. But I see it more as a hobby as I can probably fix most issues, than as a purchasing strategy I'd recommend to non technical people for instance.
If you're really concerned, you can buy two $100 secondhand laptops. If one fails, you can use the other. Good secondhand laptops in that price range will be more like 8 or 10 years old, but still usable as basic daily computers.
I've had an excellent experience using secondhand business-class laptops. Several nonprofits I'm involved have nothing but these sorts of laptops, and I've only used secondhand laptops since 2019.
I guess I'm just lucky because none of the 8 laptops I've bought used off ebay in the last 13 years have failed yet.