Switch and bait.
Some years ago a friend bought what he thought was a £30 Nokia from a well known telco's high street outlet.
Few days later we checked the receipt for his phone when we spotted a similar but different looking phone with that model number in another shop's window. Turns out the telco boys had sold him a £20 Nokia for £30.
Returning to the telco shop, noticed that the guy who'd served my friend ducked into the back office as we entered. Manager "explained" that the error had been spotted after my friend had left -- but they hadn't thought to ring him about it. No apology was offered and they still tried to charge £8 for the USB cable that Nokia hadn't included.
Convinced that these jerks had been pulling this switch ever since spotting how similar these Nokia models looked -- assuming few would notice the difference (the poor camera performance was obvious immediately).
Biting the hand that feeds IT
