There are some smaller hacks where I will never pay for.
On the other hand there are some aeeeeh lets say script that are so huge that this is more than a simple 3 liner hack.
If I want this functionality its up to me to decide if its worth the price or not but I will never blame an author to make a commercial hack out of a free one.
Its very time intensive to write a hack and its more time intensive to support it.
There is only one thing I really hate.
IF I buy a script and support and documentation are bad.
I really hate this. I understand that for free hacks the support can be limited but If I buy a hack I will be treated as customer and I want help if the stuff is not working
So everyone who is going to make a free hack a commercial one should do it if he/she can support it also...