The RMI Proxy API is a free download.

RMI Proxy Plus! 1.3  $US500 per proxy

Volume discounts $ASK. Reseller enquiries $ASK.
All enquiries to sales@rmiproxy.com

To purchase RMI Proxy:

(1)Download the RMI Replacer (free).

The RMI Replacer is a required module for the RMI Proxy. It is a tiny  modification to Sun's RMI transport which allows the RMI Proxy to modify the RMI output stream. 

This download is free, being modified Sun code. Use at own risk. 

(2)Download the RMI Proxy API (Free) (Documentation online or zip.)

(3)Agree to the licence and purchase. You cannot purchase RMI Proxy without first agreeing to the license conditions. 

(4) You will then be redirected to the online shop. When your purchase and download are complete you will receive a serial number which must be placed into a file called 'serial.txt' in the RMI Proxy execution directory.