Same for me.. After getting a new laptop we were supposed do deliver the old one to a recycling centre.
My first work laptop from that job served as my home server up until last month or so (about 8 years).
My second laptop I kept after quitting the job. I was also supposed to deliver it to a recycling point.
I quit that job about 4-5 years ago. I'm writing this reply from that 2nd laptop right now :)
Seems like a better use of resources than having it scrapped. I don't really consider it stealing, but I do get it's probably not 100% legal either.
Both laptops are Lenovo's.
I recently wrote a blog post about the new NAS I built myself and why I didn't choose for a RPI 4. https://jeroenpelgrims.com/diy-nas/
I think it terms of price it won't be much more expensive than an RPI NAS, but you'll get more performance and stability.
If you don't care about power usage and/or connecting stuff through USB you can also buy some older hardware instead.