The book discovers the author''s point of view at the development of the cost estimation tool for the log frame of the building. It describes main ideas and step by step creation process. The book explores and compares two type of the cost estimation: manual type and using created tool - automatic. In conclusion the book has an analysis and the advantages of the program use. The purpose of the program is to increase the sales managers efficiency. The efficiency is achieved by the time spent reduction and the user-friendly interface of the tool. The program code was developed using the combination of the Microsoft Excel and integrated development environment - Visual Basic. Considering managers needs much attention was paid to the user''s interface developing stage and the user''s guide writing. The book was written for people who would like to get acquainted with the general principles of the program creation process.