It's worth noting that you can get more or less the same functionality hosting a static site on Amazon S3 with a free CloudFlare account for CDN + JavaScript/CSS minification. Unless your site has tens of thousands of visitors a month, S3 will be essentially free -- it would take a LOT of traffic to cost more than $10/month.
Uploading the site to S3 is marginally more difficult than uploading to Forge, but if you can write HTML you can probably use one of the many GUI S3 upload tools.
I'm not trying to be a jerk about this -- I'm genuinely curious who the target customer is and how Forge (and similar sites) differentiate themselves from existing services. What problem is Forge solving?
(One way Forge is definitely different is great UI design. Props to whoever did their design work!)