If you are tired of sending the same response to different people, there is a feature in Gmail labs, called Canned Responses.
To enable it, go to settings (gear at the right of the screen, select settings), then select Labs. From the labs, go to Available Labs, and select Canned responses.
Now every time you need to answer an email, you can select a ready made response!
This new menu will appear, just under the subject:
Now you need to type (or paste) your text the first time, select the text, and Save your first canned response!
To use it, when in a new email, just select Canned responses, and the response you want to send. The text will be inserted in where your cursor is located
Now the first option is to Insert the canned response. You can also choose to Save a new response, or just delete the canned response.
Hope this helps you to accomplish more!