Creating a Price calculator using drop down boxes for multiple BOM's

I am trying to create a price calculator for a particular product line which has multiple sizes and configurations. I would like to use drop down boxes so the user can select the size, type and attachments which will be narrowed down by the previous selections. I would like the formula to be able to calculate the cost of the components based on the selections made. Based on some research I believe this can be achieved using data validation, indirect function and the vlookup function, however; I'm not quite sure how to go about this. I have attached the document I have started for reference. Any help would be greatly appreciated.

Thanks!