No, I did not copy his system because his code is private. The system you see on my box is entirely mine and coded by me. I just made something that does the same, but it's not the same code, nor it's his system.
I just got his idea and made the same soft for my own use.
So, the code is mine and I do whatever I want with it (In this case sell it or release it as a GPL for the public use). This is the reason I'm asking how much could this cost, because if it costs nothing or less that $25 I will release it as a GPL and all will be happy
