wix.com

I'm a designer, so I'm a bit of a sticker when it comes to invitations & websites matching, but I didn't have the budget to front for some of our other options. Wix.com is a free site that allows you to alter your own web templates. Our wedding website and our invitations coordinated really well with the effort that I put into it, but if you're not up for the effort, it might be smarter to find a matching set (site + invites) that's pre-made.