are these sentences correct?

John:hi

Bob:Hello,May i help you?

John:Yes,of course.This is my fiancee and i would like to buy a fabulous necklace and ring for her.

Bob:ok,just happen to have the perfect fit for you
What size shall it be?

Fiancee:i would like that big rock right there the blue one.Can we get it?

John:You meant the necklace,right?

Fiancee:Yea,the one that has the big crystal in it

John:How much does the big rock cost?

Bob:2,000 cents

John:Could you give me a discount,please?

Bob:Yes sure, today there is a special 75% buy 1 get one free.

John:Ok,here you are.

Bob:Thanks in your change.

john:You are welcome.what about the ring,honey?

Fiancee:: yes Please….Bob: there is a ring that already comes with the necklace, with no charge on it.

Bob:Here you are.