Abstract: Disclosed is a computer with a user interface, the computer including central processing units, memories, and network interfaces, a program code that performs a search and transaction based on user input, the interface displaying in conjunction with code execution, an input environment adapted to search criteria input, the criteria defining a search for desired entities, the program code establishing a search engine that searches on different web sources to generate a search result, the engine searching using a combination of different input entities, a first entity and a second entity includable in the different entities, the engine searching for the configuration, the different entities being purchasable from different web sources, the engine searching on different web sources for the combination, and presenting found configurations, the engine providing at least one order input determined by at least one found configuration, the system taking mutual dependencies between the entities into consideration.