Paint today is expensive (for quality supplies, anyway), and I expect that the paint used in the Sistine Chapel was quite good quality, due to its endurance. There was also a lot of paint used there. When Michelangelo ran out of paint, who supplied and paid for it (or the supplies required to make it), and how was it supplied? What did he do when he needed more?
EDIT: clarified that I'm interested in the economics and supply chain.