There are many different coins, a prop

There are many different coins, a prop (e.g. a vial of blood) and a scale. The hint suggests that players should find a price for a life. The vial has to be put on one side of the scale and on the other side there should be coins – as much as it is needed to balance the scale. Then, their value should be added and the total number is a combination for a padlock. (Self-promotion! You can buy a version of this puzzle from Escape Room Supplier here.)