OfficeMax offers the Texas Instruments TI-84 Plus Graphing Calculator for $99.99 with free shipping. Price subject to change.

What makes this deal hot:
You save $15 off the retail list price. That's the lowest price we could find currently. No tax in most states.

What this does & Why you need it:
Graphing calculator handles precalculus, engineering, trigonometric, and financial functions. This also comes with 1-year warranty.