How do I mark out an item/product from our inventory (and why is this not in this system or google or anywhere?!?)

Hi daymented,

Welcome to Community!  QuickBooks Online has everything you need to setup and track the items you have on hand.  I'd be glad to help!

When you set up your inventory items, you can track them when they sell by creating an invoice or a sales receipt.  You'll also be able to set reordering points, so QuickBooks will let you know when it's time to restock.  If you need to add, edit or delete an item, click here.  However, there may be times when you notice you have more or less of an item than what's indicated.  In this situation, you can add, enter or delete an inventory quantity adjustment.

Please don't hesitate to contact us if you require additional information.  Your success is our  number one goal and we're always happy to assist!

Man, everything here is so MINIMAL and DIFFICULT.
We gave a customer one free item. I don't want to stop carrying that item as a product, I'm just trying to figure out how to tell my inventory that one item is now gone because we gave it to a customer for free.

You can do an inventory adjustment, or simply make an invoice out to your customer and charge him $0.00. The invoice takes the item out of inventory, makes the adjustment to cogs and the customer doesn't have to pay anything for the item.  You don't need to make any journal entries or extra inventory adjustments.  I would make myself a note on the invoice as to why you gave them the item at no cost to them.  Simple.