When considering the cost of roofing materials, many people take into account just the shingle prices. This is incorrect, as a roof made just of roofing shingles will not work. You also need to consider all the accessories that are included in a complete roof system.
Business letters tend to have both the sender and receiver's address and the date at the top of the page and they begin with a polite salutation, such as dear Mr. and Mrs, followed by a blank line before the body or the content of the letter.
There are many services offered by the postal office. You can send your mail as regular mail, certified mail, or registered mail. Regular mail is the cheapest as you have to pay more for certified mail and registered mail. Here are other differences between certified and registered mail.