Here is an auction for a used but excellent condition TI-GRAPH LINK. 

Using this cable you will be able to utilize the full capability of your TI Graphing Calculator with the ability to back up data, create or edit programs, capture calculator screen images, transfer programs and more.  

Easy to download popular programs and calculator based laboratory (CBL) system programs from the Texas Instruments calculator archives.  

You can also create or edit programs on screen with easy access to all graphing calculator functions.  

In addition you can copy and past screen snapshots, programs or data directly into word processing files and print them out. 

Compatible with TI-73 Explorer, TI-83, TI-83 Plus, TI-83 Plus Silver Edition, TI-84 Plus, TI-84 Plus Silver Edition, TI-84 Plus C Silver Edition, TI-86, TI-89, TI-89 Titanium, TI-92, TI-92 Plus, and Voyage 200 and others.  

Uses a serial connection to your computer.  (You'll probably want to rustle up a Serial to USB adapter to make this really useful; sorry not included)