I have a website, and it's for me as a writer and my books. I have two different publishers.
I won't disageree that it's a good idea to have one. I will say that in this day and age of technology, most authors have some kind of website. Even big namers have websites, like JK Rowling (who doesn't do her own) and Jane Yolen (who does). People like to find out about the author, and with the internet it's easier than ever. It's a decent promotional tool. I also have a MySpace and two blogs.
I get a fair number of hits on both sites and the blogs, but I only pay for the website, and that's only a teeny amount of money for the domain name. Teeny, less than $20/year for my own address.
And people can find my book and it's a decent price, so it's only an adjunct to my publisher's marketing, not the only thing. That's the difference. And it doesn't have a 'freewebs.com' address, which is another dead giveaway that it's amateur hour. (Freewebs is who my site server is). Cough up the money for the domain name already, or no one will find you!
There's just a right way and a wrong way to do it.