Not that much… Gold flake is about £15 for a pack of 30 2" square sheets of gold flake for cake decorations.

Gold can be beaten to hear a few hundred atom thickness without becoming completely destroyed (https://hypertextbook.com/facts/1999/JeniferVilfranc.shtml).

1oz, which is about £1,200 give or take, can make 300 square foot of leaf. This photo shoot… Isn’t that expensive.