Just been into the Newton Aycliffe Tesco Extra where they have several major brand bluetooth headsets for just under £5.
I picked up a Sony Ericsson HBH-PV702 and a Nokia BH-303 for £4.97 each.
They had Motorola and own brand sets too, all the same price.
They are amongst the regular display of handsets and headsets.
Got an own brand bluetooth dongle for 97p too down from £10, ideal as a spare for the laptop case.
I expect this is instore only and they will fly out of the door.