buy caching license

Hi, I may buy the caching license to control the cache issue.First, plese telll me how to buy it. Contact sales@untiy3d.com?
Second, 50Mb 's share space is too small ,If I want to buy more, say ,200M around, how much may it be cost?
The last question is about its usage.
If I buy it for a domain, does it mean different webplayer under this domain will share the same caching directory?
for example: i have a host http://abc.com
then I have 3 webplayer’s
http://abc.com/a.html, host a webplayer.unity3d
http://abc.com/b.html,host a different webplayer.unity3d
http://abc.com/c.html,host another different webplayer.unity3d
if I buy the license for the domain http://abc.com ,does that mean all the 3 subdomain will benifit from the specific cache.
And if i using the Caching funciton with domain = http://abc.com name = C://unityCache
static function Authorize (name : String, domain : String, size : long, signature : String) : boolean
all the subdoman can share C://unityCache as their cache, right?

Unity FAQ
What is the Unity Caching Product and how can I license it?
Unity offers a premium extension of the Unity webplayer which caches asset bundles locally to end users. This product is licensed on a revenue-share model under a separate agreement made by our business development team. Generally, this product is licensed to developers or publishers with large online game files and online traffic. The Unity Caching Product reduces bandwidth costs and is geared towards minimizing download abandonment.

part of email from unity:

The standard licensing terms for our caching license are no license fee
upfront, with 3% of net revenue as revenue-sharing on the back end. This
is Unity’s only product with a royalty; however, most of our customers are
happy with it, as it decreases their costs while increasing their revenue.