Both agreements are legal and binding documents and are subject to clauses and conditions of the document, when signed by both the buyer and seller. An offer to purchase is more common in small transactions and the letter of intent is more common in large transactions.
Letters of intent can be used in situations where a group of students wish to organize a specific club or perhaps a new fraternity. In the letter they can state their reasons for taking this action, how many members they expect to have and what they think they are going to accomplish. The letter can also outline the requirements for membership and in many cases the basic rules of behavior that will be expected for continued membership. Students might also write a skillfully prepared letter to the admissions office of the college they wish to attend and include it with the rest of their application package.