Resin/Powder Price Trends

Hi guys, this may be an unusual kind of post but I am looking for any kind of help here as I have been searching for hours.

I’m currently working on a research paper involving 3D printing and its evolution/potential use in my industry. I’m trying to evaluate the price trends both of the 3d printers themselves and also the materials used, unfortunately, the latter has proved rather difficult to find info on so I was wondering if anyone here had any ideas that could point me in the right direction.

Generally, I’m trying to find information for the price per kg for resins, PBF powders, and binder jet powders over past years. Any help finding sites with this information or even other forums which could help would be much appreciated.