Sounds like the old scam of something for nothing.
I've heard of it being done with "easy to move goods". Here's an experience from a relative of mine recently with "sets of cutlery". Here's the gist.
Big Irish fella comes up and says "Hey mate, I've got six sets of cutlery left over from my sales today you can have a set for nothing."
Relly says "For nothing? what do you mean?"
BIF: "My boss won't let me take them back unsold but I can put them down as "promotional gifts".
Relly: (Has a look and says ok)
BIF "Can you just sign you've had them as a promotional gift?"
Relly "Ok" signs some form.
BIF "Look I can't really go back with nothing for them, they're top quality - can you give me a tenner?"
Relly "I thought they were free?"
BIF "Well I've got to explain to my boss (slightly injured but insistent look) ... "
Relly "I haven't got a tenner on me."
BIF "What have you got?"
Relly "Might scrape up a fiver"
BIF "I suppose I'll have to accept that - but I'll get into trouble with my boss."
Scam done.