A TI 83 graphing calculator is a must-have for any serious college student. Without it, passing tough classes such as Advanced Algebra, Trigonometry, Calculus I and Differential Mathematics (this is a generic list) can be extremely difficult. The problem, however, is that a TI 83 graphing calculator can't be obtained for any less than $100 -- money that you'd probably rather allocate toward other college expenses. Thankfully, the folks at Texas Instruments have released a virtual TI 83 graphing calculator that you can download and use at any time, given access to an Internet-connected computer.

Visit Texas Instrument's download page for the TI-83 Plus / TI-84 Plus / TI-73 Explorer ™ SDK. Click the "TI-83 Plus SDK" toward the bottom of your page, and then click on the "Save File" button to download and save this file to your computer.

Navigate to your Downloads folder -- on a Windows 7 machine, it can be found in the "My Documents" folder -- and double-click on "TI-83 Plus SDK."

Install the program by clicking the "Next" prompts, and reboot your computer when the installation is complete.

Click on the shortcut on your desktop labeled "TI-83 Plus Flash Debugger" to start the program.

Open the "File" menu on the upper-left side of your screen, select the "New" button, click on the option for a "TI 83" graphing calculator and then press the "OK" button.

Click on the "Play" arrow when a new window pops up to begin the TI-83 virtual graphing calculator simulator. From here on out, you'll be able to use the simulator just as if it's an actual TI-83 graphing calculator.