Seems a bit misleading, its free survey but you still pay for the insulation? Unless your on dole / benefits or pensioner which has been the case for a while!...
I've not researched whether or not Tesco scheme is 'free', but EDF definitely appear to be doing free loft and cavity insulation (for everyone) at the moment - just the usual restrictions, like current loft insulation less than 60mm, and house not 'too large'. And nPower will deliver rolls of insulation for DIY at £1 each. And no doubt there are others...
I was reminded at a meeting last week that the CERT (Carbon Emissions Reduction Target) scheme, which is why energy suppliers offer subsidised or even free insulation, is due to end in December 2012, around the time the Green Deal is due to start. The Green Deal consists of an interest bearing loan associated with the property which is paid off through energy bills (albeit arranged that energy savings more than pay for the cost of the loan), but chances are that insulation will be back to full price. So now definitely appears to be the time to get insulation if you haven't already.