Listen to the recording, learn then try to make up your own conversation changing the size, the colour and the type of cloth: dress, T-shirt, skirt, blouse………
https://learnenglishteens.britishcouncil.org/skills/listening/a2-listening/shopping-clothes

Shop assistant: Can I help you?

Customer: Yes, have you got this skirt in other colours?

Shop assistant: We’ve got it in yellow, blue, gray and green. What size do you want?

Customer: Large.                            

Shop assistant: OK, in Large we’ve got blue and gray.

Customer: And in yellow?

Shop assistant: No, just blue and gray.

Customer: OK, gray. Can I try it on?

Shop assistant: Yes, of course. The changing rooms are over there.

(pause)

Shop assistant: Is it OK?

Customer: Yes, I’ll take it.

Shop assistant: That’s 15,25USD. Would you like to pay by credit card or with cash?

Customer: Cash please. Here’s money.

Shop assistant: OK, thanks and here’s your receipt.

Customer: Thanks. Bye.