Doorway Pages and wpCloaker

Hello everyone!

So I've had wpCloaker for a while now, and I've seen people around here using it to make Doorway pages. I have a couple of noob questions.

Should I make multiple XXXXXX.wordpress.com blogs? Or would I have to purchase hosting + domains and add WP to each? OR is there an option out there where I can upload them to free hosting sites?

Also, how many site would be a good start?

Thanks,
Doug