I'd like to be somewhat vague because my job is somewhat niche. For my job I made custom products that are made up of subcomponents that cost me either by the foot, by the pair, or individually. So a particular product may include 5 feet of X, Y and Z, a pair of V and 1 of T and U. Then I add a bit for profit.

Right now I have a somewhat simple spreadsheet that has all my components and their costs listed which are then referenced on other sheets. The problem is adding or removing components is a real pain in the ass because I'd have to edit each and every sheet.

I'd like a better system where I can create a new product then from a drop down or something pick all the relevant components and enter how many of that component I need. Then create a quote that I can email to a client that lists the final cost of a bunch of products.

I'd prefer this to be a, open source web app but it can be a desktop application.