Automated Inventory Manager & Charge Sheet

Hi everyone, so I'm looking at working out something where I can use Excel to keep track of inventory, but also charge customers from a simple data entry on a single page.

Here is my thinking:  Name gets scanned from a barcode scanner, then they scan each item that is used for the person.  I need this to calculate automatically based on ID numbers and the Name of the person being scanned.  Here is what I have so far.....

Data Entry

Names & Inventory

Charge Sheet

So I kinda know the logic behind what I need, just not sure how to go about putting it into Excel statements lol:

IF charge sheet name is found in column A on Data Entry Sheet find item ID and convert it to the price from the Names & Inventory (however many times 1001 is found * price), (however many times 1002 is found * price), etc.... then print the total of the prices combined into Total Charges.

I'm sure that I can accomplish this through a LOT of hidden fields with individual formulas to find each number in each row in separate cells, then adding those all into another hidden cell...then throwing this data over here...etc...but if there is a simpler way to accomplish this I would appreciate any help.