The materials involved in a permeation study or IVPT are samples and consumables. The samples refer to the product and the pure compounds used as standards, while the consumables refer to either the chemicals (solvents, acids, bases, buffers, reactants, and others) and the membranes. The cost of samples and chemicals usually has a marginal incidence on the study, while the membranes can significantly influence the final price. The membranes are the core of the whole study and can be either artificial (cheaper but less representative) or ex vivo (more expensive and more representative). Among the ex vivo membranes, the humans are more expensive than animal ones. Among animals, swine ones are the most expensive and more rappresentative. The choice of the membranes has to be driven by the goal of the study. During formula development, artificial membranes could represent a budget option. Ex vivo swine membranes better suit the requirements for product approval. Finally, IVPT studies for bioequivalence require human membranes. In a simple study without validation with ex vivo membranes for 1 analyte and 1 formulation, sample and chemicals may contribute to the 10-15% of the final price, while the membranes for a further 15-30% and in case of an IVPT up to 50%.