I have a pretty extensive background in MS Excel w/VBA programming, so I made my own inventory spreadsheet to use in conjunction with the venues in which I sell pens. I set up tables with all the kits I use, different plating options, types of pen blanks used, extras, cases, etc, and use drop down boxes to do quick selection of these items when a pen is made. Once that happens, Excel does all the calculating for me of barebones material cost, recommended wholesale, recommended resale, and profit. I then hit a button (running VBA code in the background) that will add that item to a master inventory (mine), add it to a current inventory (vendor in which they are sold), and timestamp it all so that I know when it was added to each. If the store sells a pen, they just mark the "sold" column with anything (the letter "y" is usually the marking of choice) and hit the "move to sold" button (again, more VBA code). That moves the sold item to a sales inventory (the store's means of tracking what has been sold and what is owed to me) and a master sales inventory (my personal tracking means that helps me keep tabs on most popular kit, blank, extras, case, etc. as well as total profit made). All of this is also timestamped. I also gave the store the ability to build a custom pen with an interface similar to what I use to add items to the inventory so that they can quote custom jobs on the spot with confidence. The spreadsheet is 7 tabs, 4 tabs of which are visible to the store, and all 7 tabs visible to me with a password entry at the prompt. It works well for me as it is a fluid means of tracking inventory, when it was made, when it was sold, how much it was sold for, etc. It gives me tons of useful information as well to plan out future purchases. All that needs to happen before I take a load of new items to the store is have them send me their current version so that I can add to the current inventory, then I send it back to them, with everything still in working order.