I am looking for someone to make me a simple pricing tool

I am looking for someone to create a basic pricing tool that will help us calculate the average price of each model of laptops that we purchase.

The laptops come with a number of different variables (ie memory, Hard Drive Size, Windows 7 or Windows 10) so I would be looking to price at a base rate, the program will need a way of reducing the price should the particular model come with Windows 10) ie if purchased with Windows 10 then reduce price by £20.

We will need to keep a record of upto 30 different models.

I hope this make some sense, if you have any questions please let me know