It's my pleasure, you are welcome to use the image. You could even mention that the coin is on sale with this topic details 
I have actually long thought about putting a section to the site for coin sales. People could make sell listings there in a centralized place, much more organized then on this forum. then I could direct the buyers to the sellers, and take a small cut. Do you think this would be successful?
Could be, but it'll be a massive hassle having to keep updating when new coins get listed and sold.
It could, but He already has all the coin variations on the book, and could automate this as entry-box on website.