Should I be using SQL transactions, while reading records?

Question

SQL transactions is used for insert, update, but should it be used for reading records?

Answer 1

It's posssible to to do transactions but what is purpose of it?

You can set the appropriate isolation level for an entire SQL Server session by using the SET TRANSACTION ISOLATION LEVEL statement.

This is the syntax from SQL Server Books Online:

SET TRANSACTION ISOLATION LEVEL 
    {
        READ COMMITTED 
        | READ UNCOMMITTED 
        | REPEATABLE READ 
        | SERIALIZABLE
    }

Locking in Microsoft SQL Server.