Formal:
* شكرا جزيلا (shukran jazilan): This is the most formal and polite way to say "thank you."
Informal:
* شكرا (shukran): This is a more casual way to say "thank you."
* Merci (mersi): This is a French loanword that is commonly used in Algerian Arabic.
* شكرا بزاف (shukran bzaf): This means "thank you very much" and is a more emphatic way to express gratitude.
* بارك الله فيك (barak allah fik): This literally means "May God bless you" and is a very common way to express thanks, especially for gifts or favors.
Note: "Shukran" and "Merci" are commonly used, and they can be used in both formal and informal situations.