For me buying a preowned 13 mini, I got mine from Amazon renewed. You can get excellent condition or spend a little more and get the renewed Premium for one with battery health of 90% or greater. Then just be patient for the right one to come by . . .
The one I got looks pristine however the battery health on mine is at 81%. I purchased mine as “renewed” only which guarantees battery health of 80% or greater. I have got the equipment and new battery to do the install on my iPhone when the time comes.