Can I help you ?   I need some stamps for this letter .   What kind of stamps do you want ?   How much do I need for this letter ?   I must weigh it first . Err ... It's five grams over weigh , Do you want to send it as an ordinary or registered letter ?   I want it registered . How much is it then ?   Registration plus overnight ... err ... seven dollars in all .   Here's a 10 - dollar bill .   Now , your receipt , and the change .   Thanks . Good-bye . 