To keep down the hosting cost, a big win will be to use a CDN, to reduce the load on the primary servers. Typically you'll add a separate subdomain, e.g.
assets.hitmanforum.com which points to the CDN, which in turn will retrieve files from the server.
CloudFlare (https://www.cloudflare.com/plans/) and AWS CloudFront are both good options.
In addition, giving long cache expiry (a year or so) on the assets, coupled with the asset-fingerprinting (an md5 hash appended to CSS/JS filenames) will reduce requests. I'd guess that ~80% of requests hitting the webserver are for js/images/css.
It's easy to add: