Backoffice to alter prices

Hi there I have a small quotation system that lets me choose options like : Operating System, Number of Processors, RAM. Depending on the options I choose it will give me a price. For Example if I choose Ubuntu (operating system) and 4 processors and 8 GB of RAM it will give me a price (Ex. $389.90). Or if I choose Microsoft SQL server with 2 Processors and 4 GB of RAM it will give me different price (Ex. $129.90). I need to be able to modify the price from a UI (a back office tool) like a drop down .