Not everyone can afford the prices of a boxed set of one or more seasons of a classic tv show. One month of sattelite or cable: arond thirty bucks. Season one of any tv show: Around 30 bucks (or even much more). With Sattelite/Cable you get more for your money.
I'd like to know which show goes for 30 dollars a season. Even a season of South Park goes for 40 bucks minimum. I think I saw ER at about 60 to 70 dollars per season. And if you're interested in Star Trek (TOS or TNG) you're looking at $120 per season.
Netflix it, $20 a month and you can load your queue with all these old shows, get the unedited shows with no commercials and whatever DVD extras they put in. The TVShow on DVD thing is rewriting the whole concept of reruns.