First issue, it states that you only get the free service if their initial testing indicates that your site will get at least 2000 page loads a day. Second issue, they are going to insert advertisements (probably pop-under and/or pop-up ads) which will annoy visitors to your site. Third, they require that during the initial evaluation where they determine if your existing site generates enough traffic, you have to give the login access to your site so they can check the stats. Personally, I don't give anyone login access to my site unless I'm sure I trust them.
If you want a dedicated host but cannot afford one, look into a virtual private server (VPS) option from a reputable hosting provider, which will give you what may be a reasonable facsimile of a dedicated server at some intermediate price point.