I will be launching my website by the end of the year, and I believe that I have found the perfect web host and subdomains.
HostUltra (click here) give you unlimited webspace and bandwidth, and are completly free. They don't have any pop-ups or banners, but a pop-UNDER instead, that only shows when your visitors exit their browser. They also ask for a minimum of 10 visitors per week to your website.
These have decent enough subdomains, but I think I have found a far better one, that is again totally free.
.co.nr (click here) may not use a British or international suffix (they use Nauru's), but is still short enough to easily remember. They do ask for a small banner (88 x 31 pixels), and I think they may also have pop-under adverts. These only ask for 1 visitor per month unlike the .TK domain.