its not as elegant a solution as dropbox or google drive (Google also recently stopped allowing webhosting on Drive.) for preview hosting.
but so far the best free thing I found was x10hosting
its one of the better free website hosting sites. and you don't have to actually set up a website. they give you a subdomain and you can just set up as many sub sub domain sites within your subdomain as you want and host games on each on each of them. The only hassle is that you have to use FTP to upload to the server. but the added bonus is if you have good content you can supplement with a nice front end website (can use their templates if you like) and establish some web presence.