According to this, Weebly (YC startup) has over 1 million users and "well over 1%" of those are paying users. That might mean 1.1% or it might mean 5%...but apparently they've got at least 10k paying users. Not sure how much their paid plans are...
the monthly plan for weebly is $3.99 I believe. They also very smartly push buying domain names, which they surely get a couple of bucks yearly on. 40k per month is quite nice.
http://venturebeat.com/2008/11/03/weebly-scores-1-million-us...