You give them a Paypal address then they run computer algoritms till they crack your password and clean you out.. Apparently.
My wife likes selling on Bumtree - no idea why. We get those SMS scams all the time, and I ALWAYS write something horrible back. I cannot help myself. Last guy wanted to pay my wife $30,000 FOR A PAIR OF LADIES HIGH HEEL SHOES....I said sure, send it, and I'll send when the money clears and I close my account...
The best we ever got was a GENUINE buyer. Wanted us to deliver the item - a $15 bread maker - and it was *ONLY* a 2 hr drive. She begged us to, as she really needed it, but did not drive etc.