An offer is any binding or non-binding promise for the provision of supplies or services for a potential contractor against payment. An offer generally includes an indication of the technical execution of the supplies and services offered (technical offer / technical part), the methodology, organization and delivery dates (settlement offer / settlement part), commercial terms (commercial offer / commercial part), a discussion the specific advantages and other circumstances of the offer (accompanying letter) .In exceptional cases, financing of the project may also be offered. This information can be summarized in one document or contained in separate individual documents that may have been handed out at different times. A binding offer usually defines a total fixed price or a compensation based on expenditure at fixed hourly rates / percentage fees with guaranteed quality features and deadlines. The offer must therefore be designed so that it can be considered as a draft contract. A non-binding offer defines a target or budget price and expected values for quality / properties and deadline without warranty. It has an informative character and serves the interested party primarily to assess the profitability of his investment project. Offers are usually made free of charge and without obligation for the interested party. In special cases (for example, if the project has too low chances of realization or special demands exceeding the usual extent with regard to the quality of the offer), payment of the costs for the preparation of the offer may also be considered. This is especially true for non-binding offers, which are often also developed as part of a paid study.