Deep freezers get good prices. They can look like c&@p and still get a good price as long as the door seal is still good.

I was given a fridge that had been 'fixed up' but they still had revisations about it....
I took me 6 months to figure out that they had swapped the door for a good one with a good seal, but the inside shelf was different and when the door was shut the light was staying on...
Normally the shelf hit the butter box door which hits the light switch to 'Off' when the doors shut.

You will probably need a recording unit of some sort (Theres probably a 'App' for it now.. 8+) ) That will record tempatures over a period of time so you can 'see' what the fridge is doing as it goes thru its cycles.

Door seals and faulty contacts account for 85% of the fridges that get thrown out.