диалог на тему: shopping используя как можно больше слова: must, could,can, should

seller: Hello. Can i help you?

you: I must buy black shoes.

seller: So these shoes.

you: How much?

seller: 20 $

you: But i only have  17 $

seller: Sorry, we couldn't help you

you: But i should buy these shoes. These present for my brother.

seller: So for these we can doing salle. You can buy these shoes for 17 $

you: Thank you very much. You help me.

seller:  Please, come again.

you: Bay, good luck.