There are some free CDNs in the Web.
CloudFlare protects and accelerates any website online. Once your
website is a part of the CloudFlare community, its web traffic is
routed through our intelligent global network. We automatically
optimize the delivery of your web pages so your visitors get the
fastest page load times and best performance. We also block threats
and limit abusive bots and crawlers from wasting your bandwidth and
server resources. The result: CloudFlare-powered websites see a
significant improvement in performance and a decrease in spam and
CoralCDN is a free and open content distribution network based around
peer-to-peer technologies, comprised of a world-wide network of web
proxies and nameservers. It allows a user to run a web site that
offers high performance and meets huge demand, all for the price of a
$50/month cable modem.
Publishing through CoralCDN is as simple as appending a short string
to the hostname of objects' URLs; a peer-to-peer DNS layer
transparently redirects browsers to participating caching proxies,
which in turn cooperate to minimize load on the source web server.
CoralCDN proxies automatically replicate content as a side effect of
users accessing it, improving its availability. Using modern
peer-to-peer indexing techniques, CoralCDN will efficiently find a
cached object if it exists anywhere in the network, requiring that it
use the origin server only to initially fetch the object once.