Reduce the cost for using on more than one computer

I'm a developer and work in both Mac and Windows products. I used to carry both a Windows laptop and a Macbook Pro when traveling, so that I could work on both platforms. Parallels has been great, since I now only need to carry a single machine with me, but I am planning to replace my home computer and would like to get an iMac. However that would mean I have to cough up another $99 (or $135 Canadian dollars!) to use Parallels on my home machine. The machines would not be used at the same time, and would not be used by anyone else, but Parallels requires that I buy two licenses.

Most of the software I use allows me to install on more than one machine; this seems like a logical step here.