Not "Not Working until proven otherwise." Just "Not Working."
You show me that it works, or kinda works, it's a different story.
If he, or anyone, wants more than "$5-10" (maybe 20 on a good day), he needs to be able to say that it works, and back that up in case it arrives and it doesn't.
All it is now is a rusty workbench display item. $5-10.