You need to have a bunch of hosting accounts to run your Wordpress blogs from. The more accounts the better, as the more IP addresses you use, the less likely it is that the search engines will associate your blogs together. These are the best cheap hosting accounts we have found so far:-
$3.45 a month, free domain, good for 5 Wordpress blogs
$3.95 a month, good for 5 Wordpress blogs
$6.95 a month, good for 5 Wordpress blogs, free domain
$6.95 a month, good for 5 Wordpress blogs
note that you can, if you wish, put more than this number of blogs on these hosts, but the suggested numbers are the most we'd actually recommend.