The link below is a good starting place for prospective student members. The IET has created a special area on their web site just for student members. There is plenty of information contained here.

http://www.theiet.org/students/index.cfm

The benefits of student membership are listed here:

http://www.theiet.org/membership/types/student/

This will explain what students get for their subscription fee. There is more emphasis and benefit these days on engineers belonging to a professional organisation. There are many selling points of the IET, three of the main ones being

1. The IET has global reach (excellent if you intend to work overseas).
2. The journals are excellent and are available to cover specialist areas of engineering.
3. There is a professional development track that can lead to the highly regarded qualification of Chartered Engineer.

Also note membership of the IET can benefit first year students (and all other year groups) all the way through to their final year.