The contracting authority has an obligation to have procurement practice that contributes to reduce the impact of the environment and promote climate-friendly systems where relevant, c.f. the Public Procurement Act § 5. In this case purchasing used will have large savings for the environment. The procurement regulations are not directly adapted to purchasing used, so we have assessed the procedure based on the basic principles in the Procurement Act. In order to ensure competition, equal treatment, predictability, verifiability and proportionality, we have chosen to compare ads from companies and marketplaces.