I need some help!! I really struggle with completing orders at the shows. I make math mistakes - calculator input errors - recheck and recheck... and as a result it takes forever for each customer! (I live in Alaska, so shipping is NOT a matter of $4.00 - it is 15% plus $2!!) I like the idea of bringing the my laptop, and I will do that whenever possible. Does anyone have a great system for fast and accurate check-out manually????!!! I hate the impression I feel like I am making at that point...