I'll let you know if I ever figure out if you can make copies, redistribute the software, or use it commercially. The license makes that REAL hard to understand, chock full of useless legalese doublespeak.
I think at least part of the problem is that the author has used software to translate from German to English, both the website and the license. The syntax is pretty unique, and is often very close to good, common English usage, so it's either pretty good software, or the author is translating a few words and phrases here and there. Maybe a German speaker can confirm this.
Freeware: With the exception of customized software requests, all of the downloads except ImageConverter Pro and TextConverter Pro (both of which are pretty clearly marked as payware on their download pages) are freeware.
You can copy and redistribute but not modify freeware. Commercial use requires written consent of Stefan Trost after a donation "based on a similar product that was purchased in the private sector and must include at least 15 euros per workplace, time period, and transaction".
On the other hand, there's this text on the "Donate" page:
Alternative support: Perhaps you do not like any of the three described possibilities, but nevertheless you would like to support us. In this case, there are many alternatives, simply take one of your talents and help us! For example, if you are a jurist, you can check elements of our general Terms and Conditions, if you know about the English language, you can check our English pages for faults. Come up with something and write us!
Perhaps you can get a license for commercial use if you help out with the English or the terms and conditions!
Also, I'm a little confused by some of the product descriptions. Example: what the @#$% does slippy clerk do? I read the description twice -- maybe I've gone cross-eyed from trying to read the license. Specialized programs that do unique things like this call for a video howto of some kind.
Based on the screenshots, it looks to me like a program that can create text interspersed with a series of numbers, which you could do similarly with Excel (put your text in one column, then use the "fill series" to put a sequence of evenly spaced numbers in the next column). It doesn't seem to use a hotkey, just that "copy to clipboard" button.
I think there are some nifty, unique little tools there, but I don't see a need for Slippy Clerk.