What is the difference between a Microsoft Office dick and a product key card?

: What is the difference between a Microsoft Office dick and a product key card?
I am planning on buying Microsoft Office 2010, but there are two Microsoft Offices. One is a Home & Student product key card and the second one just says Home & Student. What is the product key card and what is the difference between Home & Student and the key card? Can the Microsoft Ofiice 2010 Home & Student software be installed on several compuers unlimited or is there a limit on the instalation? Can the product key card code be reused without limit?
I meant disk, not dick.
I meant disk, not dick.

Answers and Views:

Answer by ELfaGeek
The Key Card assumes you already installed the trial version of MS-Office 2010 Home and Student, and lets you Activate it on up to 3 computers.

The full version includes the DVD, and lets you Activate it on up to 3 computers.

But, Open Office 3, and Libre Office, are virtually 100% file-compatible with MSO, and they’re both free, and you can freely install them on hundreds of PCs. So, just Google for them, before you waste your money.