
There are a few ways to complete this task.
The easiest way is to simply in the last year of College/University go obtain a new student ID. do not shave for a week before and you will look much older in the picture.
You now can enjoy student prices for years!
Another way is to simply download a free student ID maker from online. Print out a nice colour copy fitting the size of any plastic card you have in your wallet. (petsmart, Wallmart, Old credit card) and use the cheap mans laminate. (Take a strip of large boxing tape and place the card on it. Then using a second strip of tape sandwich the card between the 2 pieces and trim. Now it looks like it has been professionally laminated)

The third way and most pain full is to simply go on google and have a card made for 5$ from one of the many companies that will create custom cards. Put the name of a institute out of state and have a modern picture on it. Almost all non government places can not and do not confirm if student Id's are legit so you can reap the benefits of behind a adult student for the low price of under 5$!
Of course if you are desperate and don't mind shelling out 15$ you can always visit a site like this and get a international student card.
http://fakeidentification.co.uk/fake-id-cards-Student/fake-identification.php ( I do not endorse this site at all. It is simply a example )
Any way you do it make sure you use it for good and nothing illigal.
These cards should only be meant to tease your friends with and fool your parents that own a family business into giving you discounts on already free services.