Used market can be hit or miss. Definitely want to ensure the PC runs stable if you choose to go that route. Additionally you could check Costco/Sams club for some pretty solid pre built PCs. They also have an exceptional return policy. Building your own is fun and my preference, but could be daunting if you’ve never done it before.
I’d suggest costco pre built or finding a good deal via facebook marketplace or another used one that you could end up upgrading