Whirly - first reaction I usually get from people when they learn that I fly is the "isn't that horribly expensive ?", followed by the inevitable mistaken assumption that I must be loaded. Quite the reverse, as you pointed out - having spent what little money I have left on flying !!
Now I just tell people that it's about ten times as expensive as making a mobile phone call, or perhaps twice as expensive (per hour) as driving a new car up the motorway.
Takes 'em a while to figure that out - anyway, I know which I'd rather be doing !