Tomorrow is Mocky's birthday...

A: Can I help you? 
Ken: Yes. Do you have caps?
A: Yes, we have some. 
Ken: These caps are very beautiful.
A: They are new style. Many people like them.
Ken: How much is it ? 
A: It's 20 yuan .
Ken: It's too expensive. I want to buy two caps. Can you give me a discount?
A: Of course. 
Ken: How much are they?
A: They are 30 yuan. What size do you want?
Ken: Size 10. I'll take them. Thank you!