补全对话：根据对话内容与上下文，在空白处填入适当的词，使对话意思完整。每空只填一词。

A: Can I 1______ you?

B: Yes, please. I want five stamps.

A: OK.

B: I 2______ five envelopes, too. I want to 3______ some letters. Do you have some?

A: Sure. Here you are.

B: 4______ 5______ are these things?

A: Five yuan, please.

B: Thank you.