I got a leaflet through the door and it says "Free copy of The Economist & 1GB Memory stick if you call by 10th June 2011"
or Text "ECON" to 60300 and they'll call back.
Code to quote in order to get the stuff: STK35
I looked through the leaflet and there weren't any T&C of any other rules mentioned and the only things it said
"You will be charged for text at normal rate. Calls cost up to 2p/min plus 6p setup fee from BT. Mobile charges may vary. UK offer only. Lines open between 8am to 9pm, Mon- Thurs, 8am to 8pm Fri-Sun. Offer limited to one copy per UK address. Offer closes June 30th 2011."
and of course "Economist Cover for illustration only."