well... to get a bit serious...
I am an student, i dont have a steady income....
You could say "You can't afford it, then DONT buy, dont download". yeah , this way i wouldnt have discovered ALL the psychedelic goa/ambient/chill gems... except in 20-30 years from now maybe
you might say "You cant afford a car, why dont you go steal it"?
it's not the same. i dont break in a record store and steal cd's.
i download. In fact they DONT LOSE any money from me, because EVEN IF i could NOT download, i still WOULDNT BUY cuz i couldnt afford... except maybe hardly 1 cd per month.