I would say, charge by the hour, the bigger the site the more you get. Get a small sipple to use reseller account and host their sites to make a bit of cash. If you're starting out the chances of you needing massive databases are very low so a simple hosting option would be great for you to run.
Make sure you've got good understanding of a simple CMS, so many people want access to their content now it'll be a good idea for you to have one to use if you need to.
And of course, best of luck with the venture