For example, virtually any purchase made by a customer can be considered an oral contract between the contractor and the seller. For example, if you go to an establishment that sells hamburgers and makes a purchase, you probably expect that the meat is indeed hamburger meat and that it has been treated in accordance with existing food safety legislation. You don`t sign a contract every time you buy. The exchange is sufficient to create a valid transaction. However, if you become ill after eating the hamburger and it is found that the food has not been prepared in accordance with current legislation, you have the right to sue the hamburger establishment for breach of contract. .