Not only does Ergane cost nothing, but the wordlists generated with it are also free of copyright and can be copied, distributed and changed without legal restrictions. You can use them in any way you like, even for commercial purposes!
You also have the right to modify the programme and use it as a basis for developing your own software. Again, no legal restrictions are applicable here.
In order to avoid to necessity of a bilingual wordlist for every combination of the many languages that are supported by Ergane, the artificial language Esperanto is used as an intermediate language for translating from one natural language to another. Esperanto has the advantage over natural languages like English that Esperanto words having more than one meaning are very rare. Another advantage is its flexible and regular system of word-building, which makes it possible to find almost always a good equivalent for any word in any other language.
The obvious disadvantage of this system is that the extra step of translating a word first into Esperanto may occasionally cause some accuracy to be lost. But I believe that the advantage greatly outweighs the disadvantage.
Download the file Erg50.zip and copy it to a newly created directory for the Ergane files, or download Erg50.zip directly to this directory. Then use a programme like WinZip to extract the executable file and the accompanying data files. Finally you can erase Erg50.zip.
You can now run Ergane by double-clicking on the filename Ergane.exe in Explorer. If you plan to use Ergane regularly you might consider creating a short-cut to this file on your desktop.
Deinstallation of Ergane is very simple. The only thing you have to do is to remove the directory that you created for it.
Another good reason for keeping the dictionary files separate from the programme is that you do not need to download all software again (of which 99% or more may not have been changed) in order to get an update of only one or a few dictionary files.
The dictionary files must either reside in the same directory as Ergane.exe or in a subdirectory directly under the parent directory. The name of this subdirectory must be the same as the filename of the dictionary files minus the extensions. For instance, if the programme resides in a directory with the name C:\Program Files\Ergane and you want to put the dictionary files for English (English.vo0, English.vo2, etc.) into a separate directory, this directory would be C:\Program Files\Ergane\English.
There are other programmes that use the dictionary files that were originally created for Ergane. One of those is Loxias which is essentially Ergane with a lot of its functionality removed. It can still be a useful programme though, and the file Loxias.zip is a lot smaller than Erg50.zip. So, if you want to get an impression of Ergane before you decide to download the very large Erg50.zip, you might consider to try out Loxias first. And if you do not need the extra functionality that Ergane offers, Loxias may even be enough for you.