Just to add, I'm not just saying that to be defensive, I average £160-£200 most days and more on others BUT my other half earns a good salary on top of that. Could we live on just my wages, I think we could, maybe not as 'freespending' as we are now but we would certainly be OK.
I think some of the people quoting the £300 plus figure are those that have, or want, a higher standard of living then the average joe.