Systems terms matching alternative

Total cost is too much to pay so shopper decides not to purchase an item
Feedback plus input

Cashier gives incorrect change
System failure

Shopper gives item for purchase to sales agent to ring up
Input plus process

Total cost including tax
Output

Price of an item for purchase
Input

Shopper gives cashier item, which is added to all purchases by shopper, and a total cost is provided.
Input process output

Cashier inputs costs, computes totals, takes money, provides receipt.
Process

An oops sound effect
Feedback

Cashier determines cost and provides total
Process plus output