Hi,
Well, a developer spent his time developing a solution for people wanting it. It's normal he asks money for it. We can't force the developer to release his work for free. Plus, as I said, you could have a somewhat similar solution with a normal products listing.
Regarding the thank you page customization, I'm afraid I can't help with examples. I didn't see much done in that respect. Usually, merchants try to direct the users to their order and thus a simple page without too much things is preferred.
Even amazon, on their website have a pretty simple thank you page with a link to the order and a products listing below (which could be added with the Joomla modules manager and maybe a load position tag to include it where you want it in the thank you page's text.