What is a fair price?

As I mentioned, I wouldn't mind paying the $100 *except* for the fact that:

A) The piece is already used by himself and another company (although neither company is related to software development)

B) He wants to charge "significantly more" for a commercial use license. I still don't know what significantly more is, but as I mentioned to me the piece isn't worth $500 or something - especially for no exclusive rights.

Thanks for the recommendation Pongo, I figured that's what it was. I tried using the kaliedoscope filter for the Gimp but it kept crashing - the preview worked though and seemed to give me what I wanted.

I seriously don't see how I could be sued for making something similar or something "inspired from" his piece. It's not like others haven't made similar pieces. Anyways, I still intend to try and secure the piece in question but right now there are various things in my life that have higher priority with the very limited amount of money I currently make. Especially considering I'm not doing my current project with the intent of making any money.