OK, first try. Let's do this.
Amazon Cash is a way to add cash to your Amazon account. It shows up as a barcode on your phone. You take it to a participating store and buy a "gift card".
So, you've walked into a Holiday. Now what? I have yet to find a cashier who has done one yet. Try asking for an Amazon Cash gift card. When they reach for a regular gift card, show them your phone, with the bar code showing.
Tell them to "Just scan it, then it will ask how much." You can add between $15 and $500. They hit total, you give them the cash, you get a receipt.
It's that easy.
----Teresa