It depends on how you buy it. The roll is worth under $2 per kg. Cut into 12x12 sheets its worth $.50 per sheet from Alibaba. On Amazon its worth $1 per sheet. Other sizes like 8x10 or 5x7 are much more expensive. For our internal pricing I would suggest that $.50 sheet is enough.
https://www.alibaba.com/product-detail/Chinese-Factory-High-Transparency-0-2mm_62405045358.html?spm=a2700.pccps_detail.0.0.3dd95997CVHtI5
https://www.alibaba.com/product-detail/Chinese-Factory-High-Transparency-0-2mm_62405045358.html?spm=a2700.pccps_detail.0.0.3dd95997CVHtI5
https://www.amazon.ca/Samsill-Crafting-Supplies-Machines-Thickness/dp/B084HNGQPD?th=1
Here is a blurb on the plastic
https://www.clearpak.ca/site/clear-plastic-packaging-materials/pet-polyethylene-terethphalate-plastic
An important number to know is that the forming temperature is 100 C.