Hello, I guess, this is how it should be:
Hello, can I have 2kg of tomatoes please? "or" can I get 2kg of tomatoes please?
How much is it? "or" How much does it cost?
It is 120.00 DZD "or" It costs 120.00 DZD
Thank you very much, good bye. (bye "or" see you later "or" see you.)