Jess is a product of Sandia National Laboratories, which is operated under contract to the U.S. Government by Lockheed Martin Corporation. Their licensing program is really geared towards the model where someone patents something, and they license that patent to a single external company for $X dollars, where X is a large number. I'm working within the system to change it, and we've made great strides over time. The way Jess is licensed is really very close to how vertical-market software is sold in the private sector, with a few twists:
One twist, and the one that I originally insisted on, is that academic users get an academic license for free. The license lets them use Jess to learn, teach, do research, etc, but not use Jess in a product. All you have to do it apply and it's an easy process.
Another twist is that most Jess licences come with full source code. This is true of all Jess licenses except for the "trial" version (more later) and the "Special Edition" that you get free when you buy "Jess in Action." You can study the source, modify it for your own use, etc. You just can't redistribute it.
Jess licenses come with some number of free upgrades; they're really very generous.
Finally, there are no per-developer fees. You pay based on deployment, not development. All licenses are "developer" licenses.
None of the licenses get you an old or outdated version; when you get a license, you get access to the latest version and any older versions we may also choose to distribute (we still have old JDK 1.0 and 1.1-compatible versions available.)
Now, for Joe User: if you buy JIA, you get the special edition, which you can use to learn Jess. You can't use it in a product, and you don't get the source code.
If you don't buy JIA, you can download a trial version from
http://herzberg.ca.sandia.gov/jess . It's good for 30 days, no source.
The "Home Office" edition is pretty much like the "Special Edition." It costs $100.
Academic users get source code, and again, can't use the software in a product.
Now, as to commercial licenses: they still base the price for each license on the individual circumstances. I don't actually know the specific formula, but there are a lot of variables: you can pay up-front, or have a royalty-based license. You can get an internal-use-only license, or a redistribution license. You can use internally for one application, or multiple applications, servers, or sites. And so on. I try to stay out of these dealings, personally.
The quote about "reasonable" costs means that the pricing is competitive in the rule-engine industry. The actually numebrs vary widely.
