Combine multiple data sets into one master spreadsheet

Hi,

I have an workbook I use for weekly invoices where each invoice is in its own worksheet. My goal is to be able to easily make a summary sheet at the end of the month to where I can see what the charges were for each item by invoice.

The trouble comes in that each invoice doesn't necessarily have the same charges on them and each line item has a category & a subcategory as well as the value

I've attached an example spreadsheet. The first worksheet is what I would like the combined result to look like and the other two worksheets are example invoices.

Is there an easy way to do this? The real invoices are much larger and are a pain to combine by hand which is what I've been doing.

Thanks!