About a year ago, a family member bought me a new Android Galaxy S20 FE model, as a birthday gift, which cost a little more than $700 at the time. (insane gift)
Now, I think it costs $600 new, and it looks like you can find used models for $450.
This is an Android 11 device.

Shortly after that, I was working on testing mobile proxies from home, and so I bought an Android 9 phone refurbished, unlocked and rooted, from an Ebay Vendor for $200.
When I got the phone, I was surprised at the quality of the body, and the interface is of a similar quality to the 11 model.
It still surprises me that the price difference between two models is over $500.

If you care about the processor and actual hardware capability of the phone, then that might be something to consider, but if it was me, I would buy phones from reputed refurbishers on Ebay.
I have bought computers from those kinds of guys a few times, and it has always been a great experience.
There's a difference between buying a used phone from some random person, and buying a refurbished device from a trusted vendor.
I'm never spending $700 on a phone. (although the gift is appreciated)
Refurbished all the way!