Texas Instruments TI-83 Plus Graphing Calculator Reviews:
I purchased the TI-83 for my Calculus class, and it has really helped me in calc. The 83 is programmable, so you can store your formulas and basically have it as a plug and play device with whatever problem you have. Just plug it in, and it solves it automatically. Also great for trigonometry as well. A great graphing calculator.
The TI-83's are loaned to college students enrolled in math classes. Students find them easy to use, they're durable, manual is good (happy to see it is partially on line now) and meet the needs of the student and faculty requirements.