It is the busiest hour of the week and the network in your lane has never been good on a Saturday.
Eleven bills, exactly as they would be at noon. Each one is written to the phone and the sale is finished there — there is no request going anywhere, so there is nothing for a dead tower to break. A small chip on Today counts what is waiting to go up, and it goes up on its own when the signal returns. Stock comes down locally as you sell, so the twelfth customer is told the truth about what is left.
Also eleven bills, and this is the row where paper genuinely wins on the night. It needs no battery, no signal and no account, and you are faster with it than with anything else for the first fortnight. What it costs arrives later: no total that adds itself, no stock coming down, and no second copy of the evening if the book is lost or soaked.
Typically some number fewer than eleven. A server-first till treats a sale as a request — the total, the stock decrement and the receipt number are all decided by the server — so with the tower down it degrades to a spinner, a refused write, or a local cache with a limit on it. Some handle a short outage well. The failure is that you find out which kind you bought during the outage.
The columns above describe categories, not products, and that is deliberate. A claim about somebody else's app is true on the day it is written and stops being true the week they ship something — so a page with a rival's name on it ages into a false statement that we then have to be told about. What is described instead is a pattern of behaviour you can check against whatever you are actually using, in about a minute, without taking our word for any of it.
No card and nothing to cancel. Install it, sign in with your phone number, and the shop is yours from the first bill.