I bought a Pixel 4a with a cracked but still functional screen on eBay for £40. That was worth it to try it out and not an utter disaster if I had to write it off. It’s come in useful as a second phone where I don’t mind wiping it to reinstall to try out something new.
You may also find other devices with some feature broken that you don’t care about, like a broken microphone if you don’t make calls, non working or locked LTE if you always use wifi, etc