I don't have any specifics, just a feeling that there's both more and less to their story than we see here.
Caveat emptor.
You can always do an AI search to see if the Groupon offer is legit. I saw a very good OptiPlex deal, but it has Ubuntu installed by Dell. So I would have to buy a Windows 11 license.
For $10 I would give Groupon a shot.