You can't get much better than free, and TheKnot offers you a fully featured wedding website for exactly that. (Custom domains will still cost you $20 though)
With TheKnot you edit your site content in blocks, not the usual What You See Is What You Get way that you may be used to from other builders. This means you'll do a lot of saving and reloading the site to see your changes. On the plus side the blocks will act as a checklist for yourself.
Free always comes with a price though, so be prepared to be pitched to frequently, including for a photo sharing smartphone app called Veri.com, that TheKnot also owns.
