Sort of. You can download and use pyke for free under the following scenarios:
Open Source
If you are doing an open source project as defined in http://opensource.org/licenses (say you are using GPL, LGPL, MIT, Artistic license, ... for your project), you are free to use pyke for as long as your project stays open source.
Non-commercial Private Projects
If you are using pyke on a non-commercial project (say you are a student, say you are using pyke on a non-commercial pet project, ...) then you are also allowed to use pyke for as long as you want and for as many non-commercial projects as you want.
Evaluation pourposes
If you are evaluating it for a commercial project, then you can also use it. For how long? For as long as you are evaluating it. Keep in mind that if you have been evaluating it for more than a month or you are using it on a daily basis, probably you are not evaluating it anymore and you have to pay :p
For all the other scenarios, like using it on a commercial software, you’ll need to get a valid license.
Finally, even if you are using it in an open-soruce project or non-commercial project, buying it would be a way to support the project (keep in mind that pyke is really cheap).
Now, what about if you are just one or two guys, starting a company with no cash, or other situations where you think you should better spend the money somewhere else? Then treat this software as you’d like others treat your software. If you are starting to make some good money, then listen to your conscience and do the right thing.
Anyway, for any weird situation that does not fit anywhere else in this page, but a situation where you think you should be entitled to use pyke for free, then I trust your judgement! I won’t be chasing you, I know you’ll do the right thing.
Well, I devoted many hours building it, rearchitecturing it, making it faster, simpler, ... and I’d like something in exchange if you feel it is useful for you or your company.
Above all, I want this project to succeed and to improve it even further, so I count on you.
In a way, since you can download, inspect most of the source code and even you are free to change it, but you are not allowed to redistribute your changes.